diff mbox

[09/10] i915: add DP 1.2 MST support (v0.3)

Message ID 1399877207-15868-10-git-send-email-airlied@gmail.com (mailing list archive)
State New, archived
Headers show

Commit Message

Dave Airlie May 12, 2014, 6:46 a.m. UTC
From: Dave Airlie <airlied@redhat.com>

This adds DP 1.2 MST support on Haswell systems.

Notes:
a) this reworks irq handling for DP MST ports, so that we can
avoid the mode config locking in the current hpd handlers, as
we need to process up/down msgs at a better time.

b) it introduces a new MST output type.

c) it really annoys the state checker, as the connector that is
connected at the start, goes into disconnected, and its encoder
it active, and things blow up, need to look into how to solve that.

d) the intel userspace driver needs changes to use this, -modesetting
should work okay.

e) it might contain a race condition big enough to eat you.

f) its hardcoded to 4 lanes 5.4Ghz. - TODO.

Changes since v0.1:
use PORT_PCH_HOTPLUG to detect short vs long pulses
add a workqueue to deal with digital events as they can get blocked on the
main workqueue beyong mode_config mutex
fix a bunch of modeset checker warnings
acks irqs in the driver
cleanup the MST encoders

Changes since v0.3
check irq status again in work handler
move around bring up and tear down to fix DPMS on/off
use path properties.

TODO:
further state checker fixes

Signed-off-by: Dave Airlie <airlied@redhat.com>
---
 drivers/gpu/drm/i915/Makefile         |   1 +
 drivers/gpu/drm/i915/i915_dma.c       |  10 +
 drivers/gpu/drm/i915/i915_drv.h       |  14 +
 drivers/gpu/drm/i915/i915_irq.c       | 106 ++++++-
 drivers/gpu/drm/i915/intel_ddi.c      | 111 +++++--
 drivers/gpu/drm/i915/intel_display.c  |  59 +++-
 drivers/gpu/drm/i915/intel_dp.c       | 213 +++++++++++++-
 drivers/gpu/drm/i915/intel_dp_mst.c   | 530 ++++++++++++++++++++++++++++++++++
 drivers/gpu/drm/i915/intel_drv.h      |  42 ++-
 drivers/gpu/drm/i915/intel_opregion.c |   1 +
 10 files changed, 1041 insertions(+), 46 deletions(-)
 create mode 100644 drivers/gpu/drm/i915/intel_dp_mst.c

Comments

David Herrmann May 13, 2014, 7:18 a.m. UTC | #1
Hi Dave

On Mon, May 12, 2014 at 8:46 AM, Dave Airlie <airlied@gmail.com> wrote:
> From: Dave Airlie <airlied@redhat.com>
>
> This adds DP 1.2 MST support on Haswell systems.
>
> Notes:
> a) this reworks irq handling for DP MST ports, so that we can
> avoid the mode config locking in the current hpd handlers, as
> we need to process up/down msgs at a better time.
>
> b) it introduces a new MST output type.
>
> c) it really annoys the state checker, as the connector that is
> connected at the start, goes into disconnected, and its encoder
> it active, and things blow up, need to look into how to solve that.
>
> d) the intel userspace driver needs changes to use this, -modesetting
> should work okay.
>
> e) it might contain a race condition big enough to eat you.
>
> f) its hardcoded to 4 lanes 5.4Ghz. - TODO.
>
> Changes since v0.1:
> use PORT_PCH_HOTPLUG to detect short vs long pulses
> add a workqueue to deal with digital events as they can get blocked on the
> main workqueue beyong mode_config mutex
> fix a bunch of modeset checker warnings
> acks irqs in the driver
> cleanup the MST encoders
>
> Changes since v0.3
> check irq status again in work handler
> move around bring up and tear down to fix DPMS on/off
> use path properties.
>
> TODO:
> further state checker fixes
>
> Signed-off-by: Dave Airlie <airlied@redhat.com>
> ---
>  drivers/gpu/drm/i915/Makefile         |   1 +
>  drivers/gpu/drm/i915/i915_dma.c       |  10 +
>  drivers/gpu/drm/i915/i915_drv.h       |  14 +
>  drivers/gpu/drm/i915/i915_irq.c       | 106 ++++++-
>  drivers/gpu/drm/i915/intel_ddi.c      | 111 +++++--
>  drivers/gpu/drm/i915/intel_display.c  |  59 +++-
>  drivers/gpu/drm/i915/intel_dp.c       | 213 +++++++++++++-
>  drivers/gpu/drm/i915/intel_dp_mst.c   | 530 ++++++++++++++++++++++++++++++++++
>  drivers/gpu/drm/i915/intel_drv.h      |  42 ++-
>  drivers/gpu/drm/i915/intel_opregion.c |   1 +
>  10 files changed, 1041 insertions(+), 46 deletions(-)
>  create mode 100644 drivers/gpu/drm/i915/intel_dp_mst.c
>
> diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
> index b1445b7..6cf2b95 100644
> --- a/drivers/gpu/drm/i915/Makefile
> +++ b/drivers/gpu/drm/i915/Makefile
> @@ -52,6 +52,7 @@ i915-y += dvo_ch7017.o \
>           intel_crt.o \
>           intel_ddi.o \
>           intel_dp.o \
> +         intel_dp_mst.o \
>           intel_dsi_cmd.o \
>           intel_dsi.o \
>           intel_dsi_pll.o \
> diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
> index 58f2c46..3040869 100644
> --- a/drivers/gpu/drm/i915/i915_dma.c
> +++ b/drivers/gpu/drm/i915/i915_dma.c
> @@ -1677,6 +1677,13 @@ int i915_driver_load(struct drm_device *dev, unsigned long flags)
>                 goto out_mtrrfree;
>         }
>
> +       dev_priv->dp_wq = alloc_ordered_workqueue("i915-dp", 0);
> +       if (dev_priv->dp_wq == NULL) {
> +               DRM_ERROR("Failed to create our dp workqueue.\n");
> +               ret = -ENOMEM;
> +               goto out_freewq;
> +       }
> +
>         intel_irq_init(dev);
>         intel_uncore_sanitize(dev);
>
> @@ -1752,6 +1759,8 @@ out_gem_unload:
>         intel_teardown_gmbus(dev);
>         intel_teardown_mchbar(dev);
>         pm_qos_remove_request(&dev_priv->pm_qos);
> +       destroy_workqueue(dev_priv->dp_wq);
> +out_freewq:
>         destroy_workqueue(dev_priv->wq);
>  out_mtrrfree:
>         arch_phys_wc_del(dev_priv->gtt.mtrr);
> @@ -1856,6 +1865,7 @@ int i915_driver_unload(struct drm_device *dev)
>         intel_teardown_gmbus(dev);
>         intel_teardown_mchbar(dev);
>
> +       destroy_workqueue(dev_priv->dp_wq);
>         destroy_workqueue(dev_priv->wq);
>         pm_qos_remove_request(&dev_priv->pm_qos);
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 7d6acb4..b3b5864c 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -1468,6 +1468,18 @@ struct drm_i915_private {
>
>         struct i915_runtime_pm pm;
>
> +       struct intel_digital_port *hpd_irq_port[I915_MAX_PORTS];
> +       u32 hpd_port;
> +       struct work_struct dig_port_work;
> +       /*
> +        * if we get a HPD irq from DP and a HPD irq from non-DP
> +        * the non-DP HPD could block the workqueue on a mode config
> +        * mutex getting, that userspace may have taken. However
> +        * userspace is waiting on the DP workqueue to run which is
> +        * blocked behind the non-DP one.
> +        */
> +       struct workqueue_struct *dp_wq;
> +
>         /* Old dri1 support infrastructure, beware the dragons ya fools entering
>          * here! */
>         struct i915_dri1_state dri1;
> @@ -1999,6 +2011,8 @@ i915_disable_pipestat(struct drm_i915_private *dev_priv, enum pipe pipe,
>
>  void valleyview_enable_display_irqs(struct drm_i915_private *dev_priv);
>  void valleyview_disable_display_irqs(struct drm_i915_private *dev_priv);
> +bool intel_hpd_irq_event(struct drm_device *dev,
> +                        struct drm_connector *connector);
>
>  /* i915_gem.c */
>  int i915_gem_init_ioctl(struct drm_device *dev, void *data,
> diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
> index 5852dee..0b16d41 100644
> --- a/drivers/gpu/drm/i915/i915_irq.c
> +++ b/drivers/gpu/drm/i915/i915_irq.c
> @@ -963,8 +963,8 @@ static int i915_get_vblank_timestamp(struct drm_device *dev, int pipe,
>                                                      &to_intel_crtc(crtc)->config.adjusted_mode);
>  }
>
> -static bool intel_hpd_irq_event(struct drm_device *dev,
> -                               struct drm_connector *connector)
> +bool intel_hpd_irq_event(struct drm_device *dev,
> +                        struct drm_connector *connector)
>  {
>         enum drm_connector_status old_status;
>
> @@ -984,6 +984,71 @@ static bool intel_hpd_irq_event(struct drm_device *dev,
>         return true;
>  }
>
> +static int port_to_hotplug_shift(enum port port)
> +{
> +       switch (port) {
> +       case PORT_A:
> +       case PORT_E:
> +       default:
> +               return -1;
> +       case PORT_B:
> +               return 0;
> +       case PORT_C:
> +               return 8;
> +       case PORT_D:
> +               return 16;
> +       }
> +}
> +static void i915_digport_work_func(struct work_struct *work)
> +{
> +       struct drm_i915_private *dev_priv =
> +               container_of(work, struct drm_i915_private, dig_port_work);
> +       unsigned long irqflags;
> +       u32 port_bits;
> +       struct intel_digital_port *digport;
> +       int i, ret;
> +       u32 old_bits = 0;
> +       u32 hotplug_reg, hpshift;
> +       bool long_hpd = false;
> +       spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
> +       port_bits = dev_priv->hpd_port;
> +       dev_priv->hpd_port = 0;
> +
> +       hotplug_reg = I915_READ(PCH_PORT_HOTPLUG);
> +       I915_WRITE(PCH_PORT_HOTPLUG, hotplug_reg);
> +
> +       spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
> +
> +       for (i = 0; i < I915_MAX_PORTS; i++) {
> +               if (port_bits & (1 << i)) {
> +                       digport = dev_priv->hpd_irq_port[i];
> +
> +                       hpshift = port_to_hotplug_shift(i);
> +
> +                       /* if we have no HPD bits for this */
> +                       if (!((hotplug_reg >> hpshift) & PORTB_HOTPLUG_STATUS_MASK)) {
> +                               DRM_DEBUG_KMS("got not regs for port %d %08x\n", i, hotplug_reg);
> +                               continue;
> +                       }
> +
> +                       long_hpd = (hotplug_reg >> hpshift) & PORTB_HOTPLUG_LONG_DETECT;
> +
> +                       ret = intel_dp_handle_hpd_irq(digport, long_hpd);
> +                       if (ret == 1) {
> +                               /* if we get 1 fallback to old school hpd */
> +                               old_bits |= (1 << digport->base.hpd_pin);
> +                       }
> +               }
> +       }
> +
> +       if (old_bits) {
> +               spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
> +               dev_priv->hpd_event_bits = old_bits;
> +               spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
> +               schedule_work(&dev_priv->hotplug_work);
> +       }
> +}
> +
>  /*
>   * Handle hotplug events outside the interrupt handler proper.
>   */
> @@ -1381,14 +1446,29 @@ static irqreturn_t gen8_gt_irq_handler(struct drm_device *dev,
>  #define HPD_STORM_DETECT_PERIOD 1000
>  #define HPD_STORM_THRESHOLD 5
>
> +static inline enum port get_port_from_pin(enum hpd_pin pin)
> +{
> +       switch (pin) {
> +       case HPD_PORT_B:
> +               return PORT_B;
> +       case HPD_PORT_C:
> +               return PORT_C;
> +       case HPD_PORT_D:
> +               return PORT_D;
> +       default:
> +               return PORT_A; /* no hpd */
> +       }
> +}
> +
>  static inline void intel_hpd_irq_handler(struct drm_device *dev,
>                                          u32 hotplug_trigger,
>                                          const u32 *hpd)
>  {
>         struct drm_i915_private *dev_priv = dev->dev_private;
>         int i;
> +       enum port port;
>         bool storm_detected = false;
> -
> +       bool queue_dig = false, queue_hp = false;
>         if (!hotplug_trigger)
>                 return;
>
> @@ -1397,6 +1477,19 @@ static inline void intel_hpd_irq_handler(struct drm_device *dev,
>
>         spin_lock(&dev_priv->irq_lock);
>         for (i = 1; i < HPD_NUM_PINS; i++) {
> +               if (!(hpd[i] & hotplug_trigger))
> +                       continue;
> +
> +               port = get_port_from_pin(i);
> +               if (port && dev_priv->hpd_irq_port[port]) {
> +                       DRM_DEBUG_DRIVER("digital hpd port %d\n", port);
> +                       dev_priv->hpd_port |= (1 << port);
> +                       hotplug_trigger &= ~hpd[i];
> +                       queue_dig = true;
> +               }
> +       }
> +
> +       for (i = 1; i < HPD_NUM_PINS; i++) {
>
>                 if (hpd[i] & hotplug_trigger &&
>                     dev_priv->hpd_stats[i].hpd_mark == HPD_DISABLED) {
> @@ -1418,6 +1511,7 @@ static inline void intel_hpd_irq_handler(struct drm_device *dev,
>                         continue;
>
>                 dev_priv->hpd_event_bits |= (1 << i);
> +               queue_hp = true;
>                 if (!time_in_range(jiffies, dev_priv->hpd_stats[i].hpd_last_jiffies,
>                                    dev_priv->hpd_stats[i].hpd_last_jiffies
>                                    + msecs_to_jiffies(HPD_STORM_DETECT_PERIOD))) {
> @@ -1446,7 +1540,10 @@ static inline void intel_hpd_irq_handler(struct drm_device *dev,
>          * queue for otherwise the flush_work in the pageflip code will
>          * deadlock.
>          */
> -       schedule_work(&dev_priv->hotplug_work);
> +       if (queue_dig)
> +               queue_work(dev_priv->dp_wq, &dev_priv->dig_port_work);
> +       if (queue_hp)
> +               schedule_work(&dev_priv->hotplug_work);
>  }
>
>  static void gmbus_irq_handler(struct drm_device *dev)
> @@ -4014,6 +4111,7 @@ void intel_irq_init(struct drm_device *dev)
>  {
>         struct drm_i915_private *dev_priv = dev->dev_private;
>
> +       INIT_WORK(&dev_priv->dig_port_work, i915_digport_work_func);
>         INIT_WORK(&dev_priv->hotplug_work, i915_hotplug_work_func);
>         INIT_WORK(&dev_priv->gpu_error.work, i915_error_work_func);
>         INIT_WORK(&dev_priv->rps.work, gen6_pm_rps_work);
> diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
> index a5b8b76..a8728d1 100644
> --- a/drivers/gpu/drm/i915/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/intel_ddi.c
> @@ -116,7 +116,10 @@ enum port intel_ddi_get_encoder_port(struct intel_encoder *intel_encoder)
>         struct drm_encoder *encoder = &intel_encoder->base;
>         int type = intel_encoder->type;
>
> -       if (type == INTEL_OUTPUT_DISPLAYPORT || type == INTEL_OUTPUT_EDP ||
> +       if (type == INTEL_OUTPUT_DP_MST) {
> +               struct intel_digital_port *intel_dig_port = enc_to_mst(encoder)->primary;
> +               return intel_dig_port->port;
> +       } else if (type == INTEL_OUTPUT_DISPLAYPORT || type == INTEL_OUTPUT_EDP ||
>             type == INTEL_OUTPUT_HDMI || type == INTEL_OUTPUT_UNKNOWN) {
>                 struct intel_digital_port *intel_dig_port =
>                         enc_to_dig_port(encoder);
> @@ -211,6 +214,19 @@ void intel_prepare_ddi(struct drm_device *dev)
>                 intel_prepare_ddi_buffers(dev, port);
>  }
>
> +void intel_ddi_force_act(struct intel_encoder *encoder, bool state)
> +{
> +       struct drm_i915_private *dev_priv = encoder->base.dev->dev_private;
> +       enum port port = intel_ddi_get_encoder_port(encoder);
> +       u32 val;
> +       val = I915_READ(DP_TP_CTL(port));
> +       if (state == true)
> +               val |= DP_TP_CTL_FORCE_ACT;
> +       else
> +               val &= ~DP_TP_CTL_FORCE_ACT;
> +       I915_WRITE(DP_TP_CTL(port), val);
> +}
> +
>  static const long hsw_ddi_buf_ctl_values[] = {
>         DDI_BUF_EMP_400MV_0DB_HSW,
>         DDI_BUF_EMP_400MV_3_5DB_HSW,
> @@ -673,8 +689,8 @@ static int intel_ddi_calc_wrpll_link(struct drm_i915_private *dev_priv,
>         return (refclk * n * 100) / (p * r);
>  }
>
> -static void intel_ddi_clock_get(struct intel_encoder *encoder,
> -                               struct intel_crtc_config *pipe_config)
> +void intel_ddi_clock_get(struct intel_encoder *encoder,
> +                        struct intel_crtc_config *pipe_config)
>  {
>         struct drm_i915_private *dev_priv = encoder->base.dev->dev_private;
>         enum port port = intel_ddi_get_encoder_port(encoder);
> @@ -795,6 +811,20 @@ intel_ddi_calculate_wrpll(int clock /* in Hz */,
>         *r2_out = best.r2;
>  }
>
> +static int link_bw_to_pll_sel(int link_bw)
> +{
> +       switch (link_bw) {
> +       case DP_LINK_BW_1_62:
> +               return PORT_CLK_SEL_LCPLL_810;
> +       case DP_LINK_BW_2_7:
> +               return PORT_CLK_SEL_LCPLL_1350;
> +       case DP_LINK_BW_5_4:
> +               return PORT_CLK_SEL_LCPLL_2700;
> +       default:
> +               return -1;
> +       }
> +}
> +
>  /*
>   * Tries to find a PLL for the CRTC. If it finds, it increases the refcount and
>   * stores it in intel_crtc->ddi_pll_sel, so other mode sets won't be able to
> @@ -814,20 +844,19 @@ bool intel_ddi_pll_select(struct intel_crtc *intel_crtc)
>
>         intel_ddi_put_crtc_pll(crtc);
>
> -       if (type == INTEL_OUTPUT_DISPLAYPORT || type == INTEL_OUTPUT_EDP) {
> +       if (type == INTEL_OUTPUT_DP_MST) {
> +               struct intel_dp_mst_encoder *intel_mst = enc_to_mst(encoder);
> +               intel_crtc->ddi_pll_sel = link_bw_to_pll_sel(intel_mst->primary->dp.link_bw);
> +               if (intel_crtc->ddi_pll_sel == -1) {
> +                       DRM_ERROR("Link bandwidth %d unsupported\n",
> +                                 intel_mst->primary->dp.link_bw);
> +                       return false;
> +               }
> +       } else if (type == INTEL_OUTPUT_DISPLAYPORT || type == INTEL_OUTPUT_EDP) {
>                 struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
>
> -               switch (intel_dp->link_bw) {
> -               case DP_LINK_BW_1_62:
> -                       intel_crtc->ddi_pll_sel = PORT_CLK_SEL_LCPLL_810;
> -                       break;
> -               case DP_LINK_BW_2_7:
> -                       intel_crtc->ddi_pll_sel = PORT_CLK_SEL_LCPLL_1350;
> -                       break;
> -               case DP_LINK_BW_5_4:
> -                       intel_crtc->ddi_pll_sel = PORT_CLK_SEL_LCPLL_2700;
> -                       break;
> -               default:
> +               intel_crtc->ddi_pll_sel = link_bw_to_pll_sel(intel_dp->link_bw);
> +               if (intel_crtc->ddi_pll_sel == -1) {
>                         DRM_ERROR("Link bandwidth %d unsupported\n",
>                                   intel_dp->link_bw);
>                         return false;
> @@ -981,8 +1010,7 @@ void intel_ddi_set_pipe_settings(struct drm_crtc *crtc)
>         int type = intel_encoder->type;
>         uint32_t temp;
>
> -       if (type == INTEL_OUTPUT_DISPLAYPORT || type == INTEL_OUTPUT_EDP) {
> -
> +       if (type == INTEL_OUTPUT_DISPLAYPORT || type == INTEL_OUTPUT_EDP || type == INTEL_OUTPUT_DP_MST) {
>                 temp = TRANS_MSA_SYNC_CLK;
>                 switch (intel_crtc->config.pipe_bpp) {
>                 case 18:
> @@ -1004,6 +1032,21 @@ void intel_ddi_set_pipe_settings(struct drm_crtc *crtc)
>         }
>  }
>
> +void intel_ddi_set_vc_payload_alloc(struct drm_crtc *crtc, bool state)
> +{
> +       struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
> +       struct drm_device *dev = crtc->dev;
> +       struct drm_i915_private *dev_priv = dev->dev_private;
> +       enum transcoder cpu_transcoder = intel_crtc->config.cpu_transcoder;
> +       uint32_t temp;
> +       temp = I915_READ(TRANS_DDI_FUNC_CTL(cpu_transcoder));
> +       if (state == true)
> +               temp |= TRANS_DDI_DP_VC_PAYLOAD_ALLOC;
> +       else
> +               temp &= ~TRANS_DDI_DP_VC_PAYLOAD_ALLOC;
> +       I915_WRITE(TRANS_DDI_FUNC_CTL(cpu_transcoder), temp);
> +}
> +
>  void intel_ddi_enable_transcoder_func(struct drm_crtc *crtc)
>  {
>         struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
> @@ -1083,7 +1126,19 @@ void intel_ddi_enable_transcoder_func(struct drm_crtc *crtc)
>                    type == INTEL_OUTPUT_EDP) {
>                 struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
>
> -               temp |= TRANS_DDI_MODE_SELECT_DP_SST;
> +               if (intel_dp->is_mst) {
> +                       temp |= TRANS_DDI_MODE_SELECT_DP_MST;
> +               } else
> +                       temp |= TRANS_DDI_MODE_SELECT_DP_SST;
> +
> +               temp |= DDI_PORT_WIDTH(intel_dp->lane_count);
> +       } else if (type == INTEL_OUTPUT_DP_MST) {
> +               struct intel_dp *intel_dp = &enc_to_mst(encoder)->primary->dp;
> +
> +               if (intel_dp->is_mst) {
> +                       temp |= TRANS_DDI_MODE_SELECT_DP_MST;
> +               } else
> +                       temp |= TRANS_DDI_MODE_SELECT_DP_SST;
>
>                 temp |= DDI_PORT_WIDTH(intel_dp->lane_count);
>         } else {
> @@ -1100,7 +1155,7 @@ void intel_ddi_disable_transcoder_func(struct drm_i915_private *dev_priv,
>         uint32_t reg = TRANS_DDI_FUNC_CTL(cpu_transcoder);
>         uint32_t val = I915_READ(reg);
>
> -       val &= ~(TRANS_DDI_FUNC_ENABLE | TRANS_DDI_PORT_MASK);
> +       val &= ~(TRANS_DDI_FUNC_ENABLE | TRANS_DDI_PORT_MASK | TRANS_DDI_DP_VC_PAYLOAD_ALLOC);
>         val |= TRANS_DDI_PORT_NONE;
>         I915_WRITE(reg, val);
>  }
> @@ -1160,6 +1215,11 @@ bool intel_ddi_get_hw_state(struct intel_encoder *encoder,
>         u32 tmp;
>         int i;
>
> +       if (encoder->type == INTEL_OUTPUT_DISPLAYPORT) {
> +               if (enc_to_intel_dp(&encoder->base)->is_mst)
> +                       return false;
> +       }
> +
>         power_domain = intel_display_port_power_domain(encoder);
>         if (!intel_display_power_enabled(dev_priv, power_domain))
>                 return false;
> @@ -1498,10 +1558,15 @@ void intel_ddi_prepare_link_retrain(struct drm_encoder *encoder)
>                         intel_wait_ddi_buf_idle(dev_priv, port);
>         }
>
> -       val = DP_TP_CTL_ENABLE | DP_TP_CTL_MODE_SST |
> +       val = DP_TP_CTL_ENABLE |
>               DP_TP_CTL_LINK_TRAIN_PAT1 | DP_TP_CTL_SCRAMBLE_DISABLE;
> -       if (drm_dp_enhanced_frame_cap(intel_dp->dpcd))
> -               val |= DP_TP_CTL_ENHANCED_FRAME_ENABLE;
> +       if (intel_dp->is_mst)
> +               val |= DP_TP_CTL_MODE_MST;
> +       else {
> +               val |= DP_TP_CTL_MODE_SST;
> +               if (drm_dp_enhanced_frame_cap(intel_dp->dpcd))
> +                       val |= DP_TP_CTL_ENHANCED_FRAME_ENABLE;
> +       }
>         I915_WRITE(DP_TP_CTL(port), val);
>         POSTING_READ(DP_TP_CTL(port));
>
> @@ -1732,6 +1797,8 @@ void intel_ddi_init(struct drm_device *dev, enum port port)
>         intel_encoder->cloneable = 0;
>         intel_encoder->hot_plug = intel_ddi_hot_plug;
>
> +       dev_priv->hpd_irq_port[port] = intel_dig_port;
> +
>         if (init_dp)
>                 dp_connector = intel_ddi_init_dp_connector(intel_dig_port);
>
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index 75b2aaf..dfcc78e 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -56,6 +56,14 @@ static int intel_framebuffer_init(struct drm_device *dev,
>                                   struct drm_mode_fb_cmd2 *mode_cmd,
>                                   struct drm_i915_gem_object *obj);
>
> +static struct intel_encoder *intel_find_encoder(struct intel_connector *connector, int pipe)
> +{
> +       if (!connector->mst_port)
> +               return connector->encoder;
> +       else
> +               return &connector->mst_port->mst_encoders[pipe]->base;
> +}
> +
>  typedef struct {
>         int     min, max;
>  } intel_range_t;
> @@ -3821,6 +3829,9 @@ static void haswell_crtc_enable(struct drm_crtc *crtc)
>         if (intel_crtc->config.has_pch_encoder)
>                 lpt_pch_enable(crtc);
>
> +       if (intel_crtc->config.dp_encoder_is_mst)
> +               intel_ddi_set_vc_payload_alloc(crtc, true);
> +
>         for_each_encoder_on_crtc(dev, crtc, encoder) {
>                 encoder->enable(encoder);
>                 intel_opregion_notify_encoder(encoder, true);
> @@ -3869,6 +3880,9 @@ static void ironlake_crtc_disable(struct drm_crtc *crtc)
>
>         intel_disable_pipe(dev_priv, pipe);
>
> +       if (intel_crtc->config.dp_encoder_is_mst)
> +               intel_ddi_set_vc_payload_alloc(crtc, false);
> +
>         ironlake_pfit_disable(intel_crtc);
>
>         for_each_encoder_on_crtc(dev, crtc, encoder)
> @@ -4038,6 +4052,23 @@ static void i9xx_pfit_enable(struct intel_crtc *crtc)
>         for ((domain) = 0; (domain) < POWER_DOMAIN_NUM; (domain)++)     \
>                 if ((1 << (domain)) & (mask))
>
> +enum intel_display_power_domain port_to_power_domain(enum port port)
> +{
> +       switch (port) {
> +       case PORT_A:
> +               return POWER_DOMAIN_PORT_DDI_A_4_LANES;
> +       case PORT_B:
> +               return POWER_DOMAIN_PORT_DDI_B_4_LANES;
> +       case PORT_C:
> +               return POWER_DOMAIN_PORT_DDI_C_4_LANES;
> +       case PORT_D:
> +               return POWER_DOMAIN_PORT_DDI_D_4_LANES;
> +       default:
> +               WARN_ON_ONCE(1);
> +               return POWER_DOMAIN_PORT_OTHER;
> +       }
> +}
> +
>  enum intel_display_power_domain
>  intel_display_port_power_domain(struct intel_encoder *intel_encoder)
>  {
> @@ -4052,19 +4083,10 @@ intel_display_port_power_domain(struct intel_encoder *intel_encoder)
>         case INTEL_OUTPUT_HDMI:
>         case INTEL_OUTPUT_EDP:
>                 intel_dig_port = enc_to_dig_port(&intel_encoder->base);
> -               switch (intel_dig_port->port) {
> -               case PORT_A:
> -                       return POWER_DOMAIN_PORT_DDI_A_4_LANES;
> -               case PORT_B:
> -                       return POWER_DOMAIN_PORT_DDI_B_4_LANES;
> -               case PORT_C:
> -                       return POWER_DOMAIN_PORT_DDI_C_4_LANES;
> -               case PORT_D:
> -                       return POWER_DOMAIN_PORT_DDI_D_4_LANES;
> -               default:
> -                       WARN_ON_ONCE(1);
> -                       return POWER_DOMAIN_PORT_OTHER;
> -               }
> +               return port_to_power_domain(intel_dig_port->port);
> +       case INTEL_OUTPUT_DP_MST:
> +               intel_dig_port = enc_to_mst(&intel_encoder->base)->primary;
> +               return port_to_power_domain(intel_dig_port->port);
>         case INTEL_OUTPUT_ANALOG:
>                 return POWER_DOMAIN_PORT_CRT;
>         case INTEL_OUTPUT_DSI:
> @@ -10203,7 +10225,7 @@ intel_modeset_stage_output_state(struct drm_device *dev,
>                  * for them. */
>                 for (ro = 0; ro < set->num_connectors; ro++) {
>                         if (set->connectors[ro] == &connector->base) {
> -                               connector->new_encoder = connector->encoder;
> +                               connector->new_encoder = intel_find_encoder(connector, to_intel_crtc(set->crtc)->pipe);
>                                 break;
>                         }
>                 }
> @@ -10249,7 +10271,7 @@ intel_modeset_stage_output_state(struct drm_device *dev,
>                                          new_crtc)) {
>                         return -EINVAL;
>                 }
> -               connector->encoder->new_crtc = to_intel_crtc(new_crtc);
> +               connector->new_encoder->new_crtc = to_intel_crtc(new_crtc);
>
>                 DRM_DEBUG_KMS("[CONNECTOR:%d:%s] to [CRTC:%d]\n",
>                         connector->base.base.id,
> @@ -10283,7 +10305,12 @@ intel_modeset_stage_output_state(struct drm_device *dev,
>                 }
>         }
>         /* Now we've also updated encoder->new_crtc for all encoders. */
> -
> +       list_for_each_entry(connector, &dev->mode_config.connector_list,
> +                           base.head) {
> +               if (connector->new_encoder)
> +                       if (connector->new_encoder != connector->encoder)
> +                               connector->encoder = connector->new_encoder;
> +       }
>         list_for_each_entry(crtc, &dev->mode_config.crtc_list,
>                             base.head) {
>                 crtc->new_enabled = false;
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index 44df493..e1bd017 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -701,8 +701,9 @@ intel_dp_connector_unregister(struct intel_connector *intel_connector)
>  {
>         struct intel_dp *intel_dp = intel_attached_dp(&intel_connector->base);
>
> -       sysfs_remove_link(&intel_connector->base.kdev->kobj,
> -                         intel_dp->aux.ddc.dev.kobj.name);
> +       if (!intel_connector->mst_port)
> +               sysfs_remove_link(&intel_connector->base.kdev->kobj,
> +                                 intel_dp->aux.ddc.dev.kobj.name);
>         intel_connector_unregister(intel_connector);
>  }
>
> @@ -2892,6 +2893,33 @@ intel_dp_probe_oui(struct intel_dp *intel_dp)
>         edp_panel_vdd_off(intel_dp, false);
>  }
>
> +static bool
> +intel_dp_probe_mst(struct intel_dp *intel_dp)
> +{
> +       u8 buf[1];
> +
> +       if (!intel_dp->can_mst)
> +               return false;
> +
> +       if (intel_dp->dpcd[DP_DPCD_REV] < 0x12)
> +               return false;
> +
> +       _edp_panel_vdd_on(intel_dp);
> +       if (intel_dp_dpcd_read_wake(&intel_dp->aux, DP_MSTM_CAP, buf, 1)) {
> +               if (buf[0] & DP_MST_CAP) {
> +                       DRM_DEBUG_KMS("Sink is MST capable\n");
> +                       intel_dp->is_mst = true;
> +               } else {
> +                       DRM_DEBUG_KMS("Sink is not MST capable\n");
> +                       intel_dp->is_mst = false;
> +               }
> +       }
> +       edp_panel_vdd_off(intel_dp, false);
> +
> +       drm_dp_mst_topology_mgr_set_mst(&intel_dp->mst_mgr, intel_dp->is_mst);
> +       return intel_dp->is_mst;
> +}
> +
>  int intel_dp_sink_crc(struct intel_dp *intel_dp, u8 *crc)
>  {
>         struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
> @@ -2929,6 +2957,20 @@ intel_dp_get_sink_irq(struct intel_dp *intel_dp, u8 *sink_irq_vector)
>                                        sink_irq_vector, 1) == 1;
>  }
>
> +static bool
> +intel_dp_get_sink_irq_esi(struct intel_dp *intel_dp, u8 *sink_irq_vector)
> +{
> +       int ret;
> +
> +       ret = intel_dp_dpcd_read_wake(&intel_dp->aux,
> +                                            DP_SINK_COUNT_ESI,
> +                                            sink_irq_vector, 4);
> +       if (ret != 4)
> +               return false;
> +
> +       return true;
> +}
> +
>  static void
>  intel_dp_handle_test_request(struct intel_dp *intel_dp)
>  {
> @@ -2944,6 +2986,65 @@ intel_dp_handle_test_request(struct intel_dp *intel_dp)
>   *  3. Use Link Training from 2.5.3.3 and 3.5.1.3
>   *  4. Check link status on receipt of hot-plug interrupt
>   */
> +static int
> +intel_dp_check_mst_status(struct intel_dp *intel_dp)
> +{
> +       int send_event = 0;
> +       bool bret;
> +       if (intel_dp->is_mst) {
> +               u8 esi[4] = { 0 };
> +               int ret = 0;
> +               int retry;
> +
> +               mutex_lock(&intel_dp->mst_mgr.aux_lock);
> +               bret = intel_dp_get_sink_irq_esi(intel_dp, esi);
> +               mutex_unlock(&intel_dp->mst_mgr.aux_lock);
> +       go_again:
> +               if (bret == true) {
> +                       DRM_DEBUG_KMS("got esi %02x %02x %02x\n", esi[0], esi[1], esi[2]);
> +                       if (esi[1] & (DP_UP_REQ_MSG_RDY | DP_DOWN_REP_MSG_RDY))  {
> +                               ret = drm_dp_mst_hpd_irq(&intel_dp->mst_mgr, esi[1]);
> +                               if (ret == 1)
> +                                       send_event = 1;
> +                       } else
> +                               ret = 0;
> +                       send_event |= ret;
> +                       mutex_lock(&intel_dp->mst_mgr.aux_lock);
> +                       for (retry = 0; retry < 3; retry++) {
> +                               int wret;
> +                               wret = drm_dp_dpcd_write(&intel_dp->aux,
> +                                                       DP_SINK_COUNT_ESI+1,
> +                                                       &esi[1], 3);
> +                               if (wret == 3) {
> +                                       break;
> +                               }
> +                       }
> +                       mutex_unlock(&intel_dp->mst_mgr.aux_lock);
> +
> +                       mutex_lock(&intel_dp->mst_mgr.aux_lock);
> +                       bret = intel_dp_get_sink_irq_esi(intel_dp, esi);
> +                       mutex_unlock(&intel_dp->mst_mgr.aux_lock);
> +                       if (bret == true) {
> +                               DRM_DEBUG_KMS("got esi2 %02x %02x %02x\n", esi[0], esi[1], esi[2]);
> +                               if (esi[1] & (DP_UP_REQ_MSG_RDY | DP_DOWN_REP_MSG_RDY))  {
> +                                       goto go_again;
> +                               }
> +                       }
> +
> +                       if (ret == 0 && send_event)
> +                               return 1;
> +                       return ret;
> +               } else {
> +                       struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
> +                       DRM_DEBUG_KMS("failed to get ESI - device may have failed\n");
> +                       intel_dp->is_mst = false;
> +                       drm_dp_mst_topology_mgr_set_mst(&intel_dp->mst_mgr, intel_dp->is_mst);
> +                       /* send a hotplug event */
> +                       drm_sysfs_hotplug_event(intel_dig_port->base.base.dev);
> +               }
> +       }
> +       return -EINVAL;
> +}
>
>  void
>  intel_dp_check_link_status(struct intel_dp *intel_dp)
> @@ -3163,6 +3264,7 @@ intel_dp_detect(struct drm_connector *connector, bool force)
>         enum drm_connector_status status;
>         enum intel_display_power_domain power_domain;
>         struct edid *edid = NULL;
> +       bool ret;
>
>         intel_runtime_pm_get(dev_priv);
>
> @@ -3172,6 +3274,12 @@ intel_dp_detect(struct drm_connector *connector, bool force)
>         DRM_DEBUG_KMS("[CONNECTOR:%d:%s]\n",
>                       connector->base.id, drm_get_connector_name(connector));
>
> +       if (intel_dp->is_mst) {
> +               /* MST devices are disconnected from a monitor POV */
> +               status = connector_status_disconnected;
> +               goto out;
> +       }
> +
>         intel_dp->has_audio = false;
>
>         if (HAS_PCH_SPLIT(dev))
> @@ -3184,6 +3292,16 @@ intel_dp_detect(struct drm_connector *connector, bool force)
>
>         intel_dp_probe_oui(intel_dp);
>
> +       ret = intel_dp_probe_mst(intel_dp);
> +       if (ret) {
> +               /* if we are in MST mode then this connector
> +                  won't appear connected or have anything with EDID on it */
> +               if (intel_encoder->type != INTEL_OUTPUT_EDP)
> +                       intel_encoder->type = INTEL_OUTPUT_DISPLAYPORT;
> +               status = connector_status_disconnected;
> +               goto out;
> +       }
> +
>         if (intel_dp->force_audio != HDMI_AUDIO_AUTO) {
>                 intel_dp->has_audio = (intel_dp->force_audio == HDMI_AUDIO_ON);
>         } else {
> @@ -3379,6 +3497,7 @@ void intel_dp_encoder_destroy(struct drm_encoder *encoder)
>         struct drm_device *dev = intel_dp_to_dev(intel_dp);
>
>         drm_dp_aux_unregister_i2c_bus(&intel_dp->aux);
> +       intel_dp_mst_encoder_cleanup(intel_dig_port);
>         drm_encoder_cleanup(encoder);
>         if (is_edp(intel_dp)) {
>                 cancel_delayed_work_sync(&intel_dp->panel_vdd_work);
> @@ -3463,7 +3582,7 @@ bool intel_dp_is_edp(struct drm_device *dev, enum port port)
>         return false;
>  }
>
> -static void
> +void
>  intel_dp_add_properties(struct intel_dp *intel_dp, struct drm_connector *connector)
>  {
>         struct intel_connector *intel_connector = to_intel_connector(connector);
> @@ -3959,6 +4078,13 @@ intel_dp_init_connector(struct intel_digital_port *intel_dig_port,
>
>         intel_dp->psr_setup_done = false;
>
> +       /* init MST on ports that can support it */
> +       if (IS_HASWELL(dev) || IS_BROADWELL(dev)) {
> +               if (port == PORT_B || port == PORT_C || port == PORT_D) {
> +                       intel_dp_mst_encoder_init(intel_dig_port, intel_connector->base.base.id);
> +               }
> +       }
> +
>         if (!intel_edp_init_connector(intel_dp, intel_connector, &power_seq)) {
>                 drm_dp_aux_unregister_i2c_bus(&intel_dp->aux);
>                 if (is_edp(intel_dp)) {
> @@ -3989,6 +4115,7 @@ intel_dp_init_connector(struct intel_digital_port *intel_dig_port,
>  void
>  intel_dp_init(struct drm_device *dev, int output_reg, enum port port)
>  {
> +       struct drm_i915_private *dev_priv = dev->dev_private;
>         struct intel_digital_port *intel_dig_port;
>         struct intel_encoder *intel_encoder;
>         struct drm_encoder *encoder;
> @@ -4029,6 +4156,10 @@ intel_dp_init(struct drm_device *dev, int output_reg, enum port port)
>         intel_dig_port->port = port;
>         intel_dig_port->dp.output_reg = output_reg;
>
> +       /* for now only use new IRQ handling for MST capable ports */
> +       if (intel_dig_port->dp.can_mst)
> +               dev_priv->hpd_irq_port[port] = intel_dig_port;
> +
>         intel_encoder->type = INTEL_OUTPUT_DISPLAYPORT;
>         intel_encoder->crtc_mask = (1 << 0) | (1 << 1) | (1 << 2);
>         intel_encoder->cloneable = 0;
> @@ -4040,3 +4171,79 @@ intel_dp_init(struct drm_device *dev, int output_reg, enum port port)
>                 kfree(intel_connector);
>         }
>  }
> +
> +/*
> + * Handle DP IRQ close to spec recommendations
> + * Use hw to detect long vs short pulses
> + *
> + * If we get a long pulse - we need to read DPCD first
> + * If we get a short pulse - we need to check link irq/status
> + * returning 1 causes the old detect to happen for HDMI
> + */
> +int intel_dp_handle_hpd_irq(struct intel_digital_port *intel_dig_port,
> +                           bool hpd_long)
> +{
> +       struct intel_dp *intel_dp = &intel_dig_port->dp;
> +       struct drm_device *dev = intel_dig_port->base.base.dev;
> +       struct drm_mode_config *mode_config = &dev->mode_config;
> +       struct drm_connector *connector;
> +       struct intel_connector *intel_connector;
> +       bool changed = false;
> +       int ret;
> +
> +       if (!intel_dp->output_reg)
> +               return 1;
> +
> +       DRM_DEBUG_KMS("got hpd irq on port %d - %s\n", intel_dig_port->port,
> +                     hpd_long ? "long" : "short");
> +       /* we have to re-read DPCD only on a long irq */
> +       if (hpd_long) {
> +               if (!intel_dp_get_dpcd(intel_dp))
> +                       goto mst_fail;
> +
> +               intel_dp_probe_oui(intel_dp);
> +
> +               if (!intel_dp_probe_mst(intel_dp))
> +                       goto mst_fail;
> +       }
> +
> +       if (intel_dp->is_mst) {
> +               ret = intel_dp_check_mst_status(intel_dp);
> +               if (ret == -EINVAL)
> +                       return 1;
> +       } else {
> +               intel_dp_check_link_status(intel_dp);
> +               return 1;
> +       }
> +
> +       if (ret == 1) {
> +               mutex_lock(&mode_config->mutex);
> +
> +               /* send the something changed event for the correct port */
> +               list_for_each_entry(connector, &mode_config->connector_list, head) {
> +                       intel_connector = to_intel_connector(connector);
> +                       if (!intel_connector->mst_port)
> +                               continue;
> +
> +                       if (intel_connector->mst_port != intel_dp)
> +                               continue;
> +
> +                       if (intel_hpd_irq_event(dev, connector))
> +                               changed = true;
> +               }
> +               mutex_unlock(&mode_config->mutex);
> +               if (changed)
> +                       drm_kms_helper_hotplug_event(dev);
> +       }
> +       return 0;
> +
> +mst_fail:
> +       /* if we were in MST mode, and device is not there get out of MST mode */
> +       if (intel_dp->is_mst) {
> +               DRM_DEBUG_KMS("failed to get ESI - device may have failed\n");
> +               intel_dp->is_mst = false;
> +               drm_dp_mst_topology_mgr_set_mst(&intel_dp->mst_mgr, intel_dp->is_mst);
> +               drm_sysfs_hotplug_event(dev);
> +       }
> +       return 1;
> +}
> diff --git a/drivers/gpu/drm/i915/intel_dp_mst.c b/drivers/gpu/drm/i915/intel_dp_mst.c
> new file mode 100644
> index 0000000..a656c22
> --- /dev/null
> +++ b/drivers/gpu/drm/i915/intel_dp_mst.c
> @@ -0,0 +1,530 @@
> +/*
> + * Copyright © 2008 Intel Corporation
> + *             2014 Red Hat Inc.
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a
> + * copy of this software and associated documentation files (the "Software"),
> + * to deal in the Software without restriction, including without limitation
> + * the rights to use, copy, modify, merge, publish, distribute, sublicense,
> + * and/or sell copies of the Software, and to permit persons to whom the
> + * Software is furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice (including the next
> + * paragraph) shall be included in all copies or substantial portions of the
> + * Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
> + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
> + * IN THE SOFTWARE.
> + *
> + */
> +
> +#include <drm/drmP.h>
> +#include "i915_drv.h"
> +#include "intel_drv.h"
> +#include <drm/drm_crtc_helper.h>
> +#include <drm/drm_edid.h>
> +
> +bool
> +intel_dp_mst_compute_config(struct intel_encoder *encoder,
> +                           struct intel_crtc_config *pipe_config)
> +{
> +       struct intel_dp_mst_encoder *intel_mst = enc_to_mst(&encoder->base);
> +       struct intel_digital_port *intel_dig_port = intel_mst->primary;
> +       struct intel_dp *intel_dp = &intel_dig_port->dp;
> +       struct drm_device *dev = encoder->base.dev;
> +       int bpp;
> +       int lane_count, slots;
> +       struct drm_display_mode *adjusted_mode = &pipe_config->adjusted_mode;
> +       struct intel_connector *found = NULL, *intel_connector;
> +       int mst_pbn;
> +
> +       pipe_config->dp_encoder_is_mst = true;
> +       pipe_config->has_pch_encoder = false;
> +       pipe_config->has_dp_encoder = true;
> +       bpp = 24;
> +       lane_count = 4;
> +       intel_dp->link_bw = DP_LINK_BW_5_4;
> +       intel_dp->lane_count = lane_count;
> +
> +       pipe_config->pipe_bpp = 24;
> +       pipe_config->port_clock = drm_dp_bw_code_to_link_rate(intel_dp->link_bw);
> +
> +       list_for_each_entry(intel_connector, &dev->mode_config.connector_list, base.head) {
> +               if (intel_connector->new_encoder == encoder) {
> +                       found = intel_connector;
> +                       break;
> +               }
> +       }
> +
> +       if (!found) {
> +               DRM_ERROR("can't find connector\n");
> +               return false;
> +       }
> +
> +       mst_pbn = drm_dp_calc_pbn_mode(adjusted_mode->clock, bpp);
> +
> +       pipe_config->pbn = mst_pbn;
> +       slots = drm_dp_find_vcpi_slots(&intel_dp->mst_mgr, mst_pbn);
> +
> +       intel_link_compute_m_n(bpp, lane_count,
> +                              adjusted_mode->crtc_clock,
> +                              pipe_config->port_clock,
> +                              &pipe_config->dp_m_n);
> +
> +       pipe_config->dp_m_n.tu = slots;
> +       return true;
> +
> +}
> +
> +static void intel_dp_mst_mode_set(struct intel_encoder *encoder)
> +{
> +       struct intel_dp_mst_encoder *intel_mst = enc_to_mst(&encoder->base);
> +       struct intel_digital_port *intel_dig_port = intel_mst->primary;
> +
> +       intel_ddi_mode_set_dp(&intel_dig_port->base);
> +}
> +
> +static void intel_mst_disable_dp(struct intel_encoder *encoder)
> +{
> +       struct intel_dp_mst_encoder *intel_mst = enc_to_mst(&encoder->base);
> +       struct intel_connector *found = NULL, *intel_connector;
> +       struct intel_digital_port *intel_dig_port = intel_mst->primary;
> +       struct intel_dp *intel_dp = &intel_dig_port->dp;
> +       struct drm_device *dev = encoder->base.dev;
> +       int ret;
> +
> +       DRM_DEBUG_KMS("%d\n", intel_dp->active_mst_links);
> +       list_for_each_entry(intel_connector, &dev->mode_config.connector_list, base.head) {
> +               if (intel_connector->encoder == encoder) {
> +                       found = intel_connector;
> +                       break;
> +               }
> +       }
> +
> +       if (!found)
> +               return;
> +
> +       drm_dp_mst_reset_vcpi_slots(&intel_dp->mst_mgr, found->port);
> +
> +       ret = drm_dp_update_payload_part1(&intel_dp->mst_mgr);
> +       if (ret) {
> +               DRM_ERROR("failed to update payload %d\n", ret);
> +       }
> +}
> +
> +static void intel_mst_post_disable_dp(struct intel_encoder *encoder)
> +{
> +       struct intel_dp_mst_encoder *intel_mst = enc_to_mst(&encoder->base);
> +       struct intel_digital_port *intel_dig_port = intel_mst->primary;
> +       struct intel_dp *intel_dp = &intel_dig_port->dp;
> +       struct intel_connector *found = NULL, *intel_connector;
> +       struct drm_device *dev = encoder->base.dev;
> +       int ret;
> +       DRM_DEBUG_KMS("%d\n", intel_dp->active_mst_links);
> +
> +       list_for_each_entry(intel_connector, &dev->mode_config.connector_list, base.head) {
> +               if (intel_connector->encoder == encoder) {
> +                       found = intel_connector;
> +                       break;
> +               }
> +       }
> +
> +       if (!found)
> +               return;
> +
> +       ret = drm_dp_check_act_status(&intel_dp->mst_mgr);
> +       if (ret)
> +               DRM_ERROR("failed to check ACT status\n");
> +       ret = drm_dp_update_payload_part2(&intel_dp->mst_mgr);
> +       if (ret)
> +               DRM_ERROR("failed to update payloads.\n");
> +
> +       drm_dp_mst_deallocate_vcpi(&intel_dp->mst_mgr, found->port);
> +
> +       intel_dp->active_mst_links--;
> +       if (intel_dp->active_mst_links == 0) {
> +               intel_dig_port->base.post_disable(&intel_dig_port->base);
> +               intel_dp_sink_dpms(intel_dp, DRM_MODE_DPMS_OFF);
> +       }
> +}
> +
> +static void intel_mst_pre_enable_dp(struct intel_encoder *encoder)
> +{
> +       struct intel_dp_mst_encoder *intel_mst = enc_to_mst(&encoder->base);
> +       struct intel_digital_port *intel_dig_port = intel_mst->primary;
> +       struct intel_dp *intel_dp = &intel_dig_port->dp;
> +       struct drm_device *dev = encoder->base.dev;
> +       struct drm_i915_private *dev_priv = dev->dev_private;
> +       enum port port = intel_dig_port->port;
> +       int ret;
> +       uint32_t temp;
> +       struct intel_connector *found = NULL, *intel_connector;
> +       int slots;
> +       struct drm_crtc *crtc = encoder->base.crtc;
> +       struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
> +
> +       list_for_each_entry(intel_connector, &dev->mode_config.connector_list, base.head) {
> +               if (intel_connector->new_encoder == encoder) {
> +                       found = intel_connector;
> +                       break;
> +               }
> +       }
> +
> +       if (!found) {
> +               DRM_ERROR("can't find connector\n");
> +               return;
> +       }
> +
> +       DRM_DEBUG_KMS("%d\n", intel_dp->active_mst_links);
> +       if (intel_dp->active_mst_links == 0) {
> +               enum port port = intel_ddi_get_encoder_port(encoder);
> +
> +               I915_WRITE(PORT_CLK_SEL(port), intel_crtc->ddi_pll_sel);
> +
> +               intel_dp_sink_dpms(intel_dp, DRM_MODE_DPMS_ON);
> +
> +
> +               intel_dp_start_link_train(intel_dp);
> +               intel_dp_complete_link_train(intel_dp);
> +               intel_dp_stop_link_train(intel_dp);
> +       }
> +
> +       ret = drm_dp_mst_allocate_vcpi(&intel_dp->mst_mgr,
> +                                      found->port, intel_crtc->config.pbn, &slots);
> +       if (ret == false) {
> +               DRM_ERROR("failed to allocate vcpi\n");
> +               return;
> +       }
> +
> +
> +       intel_dp->active_mst_links++;
> +       temp = I915_READ(DP_TP_STATUS(port));
> +       I915_WRITE(DP_TP_STATUS(port), temp);
> +
> +       ret = drm_dp_update_payload_part1(&intel_dp->mst_mgr);
> +}
> +
> +static void intel_mst_enable_dp(struct intel_encoder *encoder)
> +{
> +       struct intel_dp_mst_encoder *intel_mst = enc_to_mst(&encoder->base);
> +       struct intel_digital_port *intel_dig_port = intel_mst->primary;
> +       struct intel_dp *intel_dp = &intel_dig_port->dp;
> +       struct drm_device *dev = intel_dig_port->base.base.dev;
> +       struct drm_i915_private *dev_priv = dev->dev_private;
> +       enum port port = intel_dig_port->port;
> +       int ret;
> +
> +       DRM_DEBUG_KMS("%d\n", intel_dp->active_mst_links);
> +
> +       if (wait_for((I915_READ(DP_TP_STATUS(port)) & DP_TP_STATUS_ACT_SENT),
> +                    1))
> +               DRM_ERROR("Timed out waiting for ACT sent\n");
> +
> +       ret = drm_dp_check_act_status(&intel_dp->mst_mgr);
> +
> +       ret = drm_dp_update_payload_part2(&intel_dp->mst_mgr);
> +}
> +
> +static bool intel_dp_mst_enc_get_hw_state(struct intel_encoder *encoder,
> +                                     enum pipe *pipe)
> +{
> +       struct intel_dp_mst_encoder *intel_mst = enc_to_mst(&encoder->base);
> +       *pipe = intel_mst->pipe;
> +       return encoder->connectors_active;
> +}
> +
> +static void intel_dp_mst_enc_get_config(struct intel_encoder *encoder,
> +                                       struct intel_crtc_config *pipe_config)
> +{
> +       struct intel_dp_mst_encoder *intel_mst = enc_to_mst(&encoder->base);
> +       struct intel_digital_port *intel_dig_port = intel_mst->primary;
> +       struct intel_crtc *crtc = to_intel_crtc(encoder->base.crtc);
> +       struct drm_device *dev = encoder->base.dev;
> +       struct drm_i915_private *dev_priv = dev->dev_private;
> +       enum transcoder cpu_transcoder = crtc->config.cpu_transcoder;
> +       u32 temp, flags = 0;
> +
> +       pipe_config->has_dp_encoder = true;
> +
> +       temp = I915_READ(TRANS_DDI_FUNC_CTL(cpu_transcoder));
> +       if (temp & TRANS_DDI_PHSYNC)
> +               flags |= DRM_MODE_FLAG_PHSYNC;
> +       else
> +               flags |= DRM_MODE_FLAG_NHSYNC;
> +       if (temp & TRANS_DDI_PVSYNC)
> +               flags |= DRM_MODE_FLAG_PVSYNC;
> +       else
> +               flags |= DRM_MODE_FLAG_NVSYNC;
> +
> +       switch (temp & TRANS_DDI_BPC_MASK) {
> +       case TRANS_DDI_BPC_6:
> +               pipe_config->pipe_bpp = 18;
> +               break;
> +       case TRANS_DDI_BPC_8:
> +               pipe_config->pipe_bpp = 24;
> +               break;
> +       case TRANS_DDI_BPC_10:
> +               pipe_config->pipe_bpp = 30;
> +               break;
> +       case TRANS_DDI_BPC_12:
> +               pipe_config->pipe_bpp = 36;
> +               break;
> +       default:
> +               break;
> +       }
> +       pipe_config->adjusted_mode.flags |= flags;
> +       intel_dp_get_m_n(crtc, pipe_config);
> +
> +       intel_ddi_clock_get(&intel_dig_port->base, pipe_config);
> +}
> +
> +static int intel_dp_mst_get_ddc_modes(struct drm_connector *connector)
> +{
> +       struct intel_connector *intel_connector = to_intel_connector(connector);
> +       struct intel_dp *intel_dp = intel_connector->mst_port;
> +       struct edid *edid;
> +       int ret;
> +
> +       edid = drm_dp_mst_get_edid(connector, &intel_dp->mst_mgr, intel_connector->port);
> +       if (!edid)
> +               return 0;
> +
> +       ret = intel_connector_update_modes(connector, edid);
> +       kfree(edid);
> +
> +       return ret;
> +}
> +
> +static enum drm_connector_status
> +intel_mst_port_dp_detect(struct drm_connector *connector)
> +{
> +       struct intel_connector *intel_connector = to_intel_connector(connector);
> +       struct intel_dp *intel_dp = intel_connector->mst_port;
> +
> +       return drm_dp_mst_detect_port(&intel_dp->mst_mgr, intel_connector->port);
> +}
> +
> +static enum drm_connector_status
> +intel_dp_mst_detect(struct drm_connector *connector, bool force)
> +{
> +       enum drm_connector_status status;
> +       status = intel_mst_port_dp_detect(connector);
> +       return status;
> +}
> +
> +static int
> +intel_dp_mst_set_property(struct drm_connector *connector,
> +                         struct drm_property *property,
> +                         uint64_t val)
> +{
> +       return 0;
> +}
> +
> +static void
> +intel_dp_mst_connector_destroy(struct drm_connector *connector)
> +{
> +       struct intel_connector *intel_connector = to_intel_connector(connector);
> +
> +       if (!IS_ERR_OR_NULL(intel_connector->edid))
> +               kfree(intel_connector->edid);
> +
> +       drm_connector_cleanup(connector);
> +       kfree(connector);
> +}
> +
> +static const struct drm_connector_funcs intel_dp_mst_connector_funcs = {
> +       .dpms = intel_connector_dpms,
> +       .detect = intel_dp_mst_detect,
> +       .fill_modes = drm_helper_probe_single_connector_modes,
> +       .set_property = intel_dp_mst_set_property,
> +       .destroy = intel_dp_mst_connector_destroy,
> +};
> +
> +static int intel_dp_mst_get_modes(struct drm_connector *connector)
> +{
> +       return intel_dp_mst_get_ddc_modes(connector);
> +}
> +
> +static enum drm_mode_status
> +intel_dp_mst_mode_valid(struct drm_connector *connector,
> +                       struct drm_display_mode *mode)
> +{
> +       /* TODO - validate mode against available PBN for link */
> +       if (mode->clock < 10000)
> +               return MODE_CLOCK_LOW;
> +
> +       if (mode->flags & DRM_MODE_FLAG_DBLCLK)
> +               return MODE_H_ILLEGAL;
> +
> +       return MODE_OK;
> +}
> +
> +struct drm_encoder *intel_mst_best_encoder(struct drm_connector *connector)
> +{
> +       WARN_ON(1);
> +       return NULL;
> +}
> +
> +static const struct drm_connector_helper_funcs intel_dp_mst_connector_helper_funcs = {
> +       .get_modes = intel_dp_mst_get_modes,
> +       .mode_valid = intel_dp_mst_mode_valid,
> +       .best_encoder = intel_mst_best_encoder,
> +};
> +
> +void intel_dp_mst_encoder_destroy(struct drm_encoder *encoder)
> +{
> +       struct intel_dp_mst_encoder *intel_mst = enc_to_mst(encoder);
> +
> +       drm_encoder_cleanup(encoder);
> +       kfree(intel_mst);
> +}
> +
> +static const struct drm_encoder_funcs intel_dp_mst_enc_funcs = {
> +       .destroy = intel_dp_mst_encoder_destroy,
> +};
> +
> +static bool intel_dp_mst_get_hw_state(struct intel_connector *connector)
> +{
> +       if (connector->encoder)
> +               return true;
> +       return false;
> +}
> +
> +static struct drm_connector *intel_dp_add_mst_connector(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port, char *pathprop)
> +{
> +       struct intel_dp *intel_dp = container_of(mgr, struct intel_dp, mst_mgr);
> +       struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
> +       struct drm_device *dev = intel_dig_port->base.base.dev;
> +       struct intel_connector *intel_connector;
> +       struct drm_connector *connector;
> +       int i;
> +
> +       intel_connector = kzalloc(sizeof(*intel_connector), GFP_KERNEL);
> +       if (!intel_connector)
> +               return NULL;
> +
> +       connector = &intel_connector->base;
> +       drm_connector_init(dev, connector, &intel_dp_mst_connector_funcs, DRM_MODE_CONNECTOR_DisplayPort);
> +       drm_connector_helper_add(connector, &intel_dp_mst_connector_helper_funcs);
> +
> +       intel_connector->unregister = intel_connector_unregister;
> +       intel_connector->get_hw_state = intel_dp_mst_get_hw_state;
> +       intel_connector->mst_port = intel_dp;
> +       intel_connector->port = port;
> +
> +       for (i = PIPE_A; i <= PIPE_C; i++) {
> +               drm_mode_connector_attach_encoder(&intel_connector->base,
> +                                                 &intel_dp->mst_encoders[i]->base.base);
> +       }
> +       intel_dp_add_properties(intel_dp, connector);
> +
> +       drm_object_attach_property(&connector->base, dev->mode_config.path_property, 0);
> +       drm_mode_connector_set_path_property(connector, pathprop);
> +       drm_reinit_primary_mode_group(dev);
> +       drm_sysfs_connector_add(&intel_connector->base);
> +       return connector;
> +}
> +
> +static void intel_dp_destroy_mst_connector(struct drm_dp_mst_topology_mgr *mgr,
> +                                          struct drm_connector *connector)
> +{
> +       struct intel_connector *intel_connector = to_intel_connector(connector);
> +       struct drm_device *dev = connector->dev;
> +       /* need to nuke the connector */
> +       mutex_lock(&dev->mode_config.mutex);
> +       intel_connector->unregister(intel_connector);
> +       drm_connector_cleanup(connector);
> +       mutex_unlock(&dev->mode_config.mutex);
> +       drm_reinit_primary_mode_group(dev);

So we leak all dynamically created objects? There's no
kfree(intel_connector) here and we cannot add it because
drm_mode_object_find() is not ref-counted. So we keep the connector in
the mode_group and wait until the final drm_mode_config_cleanup()? But
drm_connector_cleanup() already removes the connector from the
mode-group, so we eventually leak the object.

I guess you already know that dynamic DRM objects are fragile. Adding
new objects is fine, but removing them is troublesome. A quick and
easy fix would be to retain destroyed objects in the mode-group but
mark them dead. When adding new objects, we can simply reuse them in
case we have some left. Not sure, whether that's better than leaking
the object, though.

Thanks
David

> +
> +       DRM_DEBUG_KMS("\n");
> +}
> +
> +struct drm_dp_mst_topology_cbs mst_cbs = {
> +       .add_connector = intel_dp_add_mst_connector,
> +       .destroy_connector = intel_dp_destroy_mst_connector,
> +};
> +
> +static struct intel_dp_mst_encoder *
> +intel_dp_create_fake_mst_encoder(struct intel_digital_port *intel_dig_port, enum pipe pipe)
> +{
> +       struct intel_dp_mst_encoder *intel_mst;
> +       struct intel_encoder *intel_encoder;
> +       struct drm_device *dev = intel_dig_port->base.base.dev;
> +
> +       intel_mst = kzalloc(sizeof(*intel_mst), GFP_KERNEL);
> +
> +       if (!intel_mst)
> +               return NULL;
> +
> +       intel_mst->pipe = pipe;
> +       intel_encoder = &intel_mst->base;
> +       intel_mst->primary = intel_dig_port;
> +
> +       drm_encoder_init(dev, &intel_encoder->base, &intel_dp_mst_enc_funcs,
> +                        DRM_MODE_ENCODER_DPMST);
> +
> +       intel_encoder->type = INTEL_OUTPUT_DP_MST;
> +       intel_encoder->crtc_mask = 0x7;
> +       intel_encoder->cloneable = 0;
> +
> +       intel_encoder->compute_config = intel_dp_mst_compute_config;
> +       intel_encoder->mode_set = intel_dp_mst_mode_set;
> +       intel_encoder->disable = intel_mst_disable_dp;
> +       intel_encoder->post_disable = intel_mst_post_disable_dp;
> +       intel_encoder->pre_enable = intel_mst_pre_enable_dp;
> +       intel_encoder->enable = intel_mst_enable_dp;
> +       intel_encoder->get_hw_state = intel_dp_mst_enc_get_hw_state;
> +       intel_encoder->get_config = intel_dp_mst_enc_get_config;
> +
> +       return intel_mst;
> +
> +}
> +
> +static bool
> +intel_dp_create_fake_mst_encoders(struct intel_digital_port *intel_dig_port)
> +{
> +       int i;
> +       struct intel_dp *intel_dp = &intel_dig_port->dp;
> +
> +       for (i = PIPE_A; i <= PIPE_C; i++)
> +               intel_dp->mst_encoders[i] = intel_dp_create_fake_mst_encoder(intel_dig_port, i);
> +       return true;
> +}
> +
> +int
> +intel_dp_mst_encoder_init(struct intel_digital_port *intel_dig_port, int conn_base_id)
> +{
> +       struct intel_dp *intel_dp = &intel_dig_port->dp;
> +       struct drm_device *dev = intel_dig_port->base.base.dev;
> +       int ret;
> +
> +       intel_dp->can_mst = true;
> +       intel_dp->mst_mgr.cbs = &mst_cbs;
> +
> +       /* create encoders */
> +       intel_dp_create_fake_mst_encoders(intel_dig_port);
> +       ret = drm_dp_mst_topology_mgr_init(&intel_dp->mst_mgr, dev->dev, &intel_dp->aux, 16, 3, conn_base_id);
> +       if (ret) {
> +               intel_dp->can_mst = false;
> +               return ret;
> +       }
> +       return 0;
> +}
> +
> +void
> +intel_dp_mst_encoder_cleanup(struct intel_digital_port *intel_dig_port)
> +{
> +       struct intel_dp *intel_dp = &intel_dig_port->dp;
> +
> +       if (!intel_dp->can_mst)
> +               return;
> +
> +       drm_dp_mst_topology_mgr_destroy(&intel_dp->mst_mgr);
> +       /* encoders will get killed by normal cleanup */
> +}
> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> index 8e41cdc..eda5131 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -32,7 +32,7 @@
>  #include <drm/drm_crtc.h>
>  #include <drm/drm_crtc_helper.h>
>  #include <drm/drm_fb_helper.h>
> -#include <drm/drm_dp_helper.h>
> +#include <drm/drm_dp_mst_helper.h>
>
>  /**
>   * _wait_for - magic (register) wait macro
> @@ -100,6 +100,7 @@
>  #define INTEL_OUTPUT_EDP 8
>  #define INTEL_OUTPUT_DSI 9
>  #define INTEL_OUTPUT_UNKNOWN 10
> +#define INTEL_OUTPUT_DP_MST 11
>
>  #define INTEL_DVO_CHIP_NONE 0
>  #define INTEL_DVO_CHIP_LVDS 1
> @@ -207,6 +208,10 @@ struct intel_connector {
>         /* since POLL and HPD connectors may use the same HPD line keep the native
>            state of connector->polled in case hotplug storm detection changes it */
>         u8 polled;
> +
> +       void *port; /* store this opaque as its illegal to dereference it */
> +
> +       struct intel_dp *mst_port;
>  };
>
>  typedef struct dpll {
> @@ -340,6 +345,9 @@ struct intel_crtc_config {
>         bool ips_enabled;
>
>         bool double_wide;
> +
> +       bool dp_encoder_is_mst;
> +       int pbn;
>  };
>
>  struct intel_pipe_wm {
> @@ -487,6 +495,7 @@ struct intel_hdmi {
>                                struct drm_display_mode *adjusted_mode);
>  };
>
> +struct intel_dp_mst_encoder;
>  #define DP_MAX_DOWNSTREAM_PORTS                0x10
>
>  /**
> @@ -527,8 +536,17 @@ struct intel_dp {
>         unsigned long last_backlight_off;
>         bool psr_setup_done;
>         bool use_tps3;
> +       bool can_mst; /* this port supports mst */
> +       bool is_mst;
> +       int active_mst_links;
> +       /* connector directly attached - won't be use for modeset in mst world */
>         struct intel_connector *attached_connector;
>
> +       /* mst connector list */
> +       struct intel_connector *mst_connectors;
> +       struct intel_dp_mst_encoder *mst_encoders[I915_MAX_PIPES];
> +       struct drm_dp_mst_topology_mgr mst_mgr;
> +
>         uint32_t (*get_aux_clock_divider)(struct intel_dp *dp, int index);
>         /*
>          * This function returns the value we have to program the AUX_CTL
> @@ -554,6 +572,12 @@ struct intel_digital_port {
>         struct intel_hdmi hdmi;
>  };
>
> +struct intel_dp_mst_encoder {
> +       struct intel_encoder base;
> +       enum pipe pipe;
> +       struct intel_digital_port *primary;
> +};
> +
>  static inline int
>  vlv_dport_to_channel(struct intel_digital_port *dport)
>  {
> @@ -621,6 +645,12 @@ enc_to_dig_port(struct drm_encoder *encoder)
>         return container_of(encoder, struct intel_digital_port, base.base);
>  }
>
> +static inline struct intel_dp_mst_encoder *
> +enc_to_mst(struct drm_encoder *encoder)
> +{
> +       return container_of(encoder, struct intel_dp_mst_encoder, base.base);
> +}
> +
>  static inline struct intel_dp *enc_to_intel_dp(struct drm_encoder *encoder)
>  {
>         return &enc_to_dig_port(encoder)->dp;
> @@ -684,6 +714,10 @@ void intel_ddi_get_config(struct intel_encoder *encoder,
>                           struct intel_crtc_config *pipe_config);
>
>  void intel_ddi_mode_set_dp(struct intel_encoder *encoder);
> +void intel_ddi_clock_get(struct intel_encoder *encoder,
> +                        struct intel_crtc_config *pipe_config);
> +void intel_ddi_force_act(struct intel_encoder *encoder, bool state);
> +void intel_ddi_set_vc_payload_alloc(struct drm_crtc *crtc, bool state);
>
>  /* intel_display.c */
>  const char *intel_output_name(int output);
> @@ -800,6 +834,12 @@ void intel_edp_psr_disable(struct intel_dp *intel_dp);
>  void intel_edp_psr_update(struct drm_device *dev);
>  void intel_dp_set_drrs_state(struct drm_device *dev, int refresh_rate);
>
> +int intel_dp_handle_hpd_irq(struct intel_digital_port *digport, bool long_hpd);
> +void intel_dp_add_properties(struct intel_dp *intel_dp, struct drm_connector *connector);
> +
> +/* intel_dp_mst.c */
> +int intel_dp_mst_encoder_init(struct intel_digital_port *intel_dig_port, int conn_id);
> +void intel_dp_mst_encoder_cleanup(struct intel_digital_port *intel_dig_port);
>  /* intel_dsi.c */
>  bool intel_dsi_init(struct drm_device *dev);
>
> diff --git a/drivers/gpu/drm/i915/intel_opregion.c b/drivers/gpu/drm/i915/intel_opregion.c
> index acde294..bce66b2 100644
> --- a/drivers/gpu/drm/i915/intel_opregion.c
> +++ b/drivers/gpu/drm/i915/intel_opregion.c
> @@ -352,6 +352,7 @@ int intel_opregion_notify_encoder(struct intel_encoder *intel_encoder,
>         case INTEL_OUTPUT_UNKNOWN:
>         case INTEL_OUTPUT_DISPLAYPORT:
>         case INTEL_OUTPUT_HDMI:
> +       case INTEL_OUTPUT_DP_MST:
>                 type = DISPLAY_TYPE_EXTERNAL_FLAT_PANEL;
>                 break;
>         case INTEL_OUTPUT_EDP:
> --
> 1.9.0
>
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/dri-devel
Dave Airlie May 14, 2014, 12:03 a.m. UTC | #2
>
> So we leak all dynamically created objects? There's no
> kfree(intel_connector) here and we cannot add it because
> drm_mode_object_find() is not ref-counted. So we keep the connector in
> the mode_group and wait until the final drm_mode_config_cleanup()? But
> drm_connector_cleanup() already removes the connector from the
> mode-group, so we eventually leak the object.
>

Seems like freeing it should be fine, it was just an oversight,

Since any objects you get with find are only valid under mode_config.mutex,
yes some drivers mess this up, but they should be fixed.

Dave.
David Herrmann May 14, 2014, 6:05 a.m. UTC | #3
Hi

On Wed, May 14, 2014 at 2:03 AM, Dave Airlie <airlied@gmail.com> wrote:
> Since any objects you get with find are only valid under mode_config.mutex,
> yes some drivers mess this up, but they should be fixed.

Didn't know that we have such a rule. Then it's fine, of course. The
page-flip code is what worried me, but drivers ought to cancel that
when destroying connectors, anyway.

Thanks
David
Daniel Vetter May 14, 2014, 8:23 a.m. UTC | #4
On Wed, May 14, 2014 at 08:05:11AM +0200, David Herrmann wrote:
> Hi
> 
> On Wed, May 14, 2014 at 2:03 AM, Dave Airlie <airlied@gmail.com> wrote:
> > Since any objects you get with find are only valid under mode_config.mutex,
> > yes some drivers mess this up, but they should be fixed.
> 
> Didn't know that we have such a rule. Then it's fine, of course. The
> page-flip code is what worried me, but drivers ought to cancel that
> when destroying connectors, anyway.

i915 cancels/stalls for any pageflips when we switch off the crtc, so I
think we should be fine.

And the above rule is for all modeset objects except framebuffers, since
those are separately protected with refcounting and you don't even need
the big mode_config mutex to do the idr lookup.
-Daniel
diff mbox

Patch

diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
index b1445b7..6cf2b95 100644
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -52,6 +52,7 @@  i915-y += dvo_ch7017.o \
 	  intel_crt.o \
 	  intel_ddi.o \
 	  intel_dp.o \
+	  intel_dp_mst.o \
 	  intel_dsi_cmd.o \
 	  intel_dsi.o \
 	  intel_dsi_pll.o \
diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
index 58f2c46..3040869 100644
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -1677,6 +1677,13 @@  int i915_driver_load(struct drm_device *dev, unsigned long flags)
 		goto out_mtrrfree;
 	}
 
+	dev_priv->dp_wq = alloc_ordered_workqueue("i915-dp", 0);
+	if (dev_priv->dp_wq == NULL) {
+		DRM_ERROR("Failed to create our dp workqueue.\n");
+		ret = -ENOMEM;
+		goto out_freewq;
+	}
+
 	intel_irq_init(dev);
 	intel_uncore_sanitize(dev);
 
@@ -1752,6 +1759,8 @@  out_gem_unload:
 	intel_teardown_gmbus(dev);
 	intel_teardown_mchbar(dev);
 	pm_qos_remove_request(&dev_priv->pm_qos);
+	destroy_workqueue(dev_priv->dp_wq);
+out_freewq:
 	destroy_workqueue(dev_priv->wq);
 out_mtrrfree:
 	arch_phys_wc_del(dev_priv->gtt.mtrr);
@@ -1856,6 +1865,7 @@  int i915_driver_unload(struct drm_device *dev)
 	intel_teardown_gmbus(dev);
 	intel_teardown_mchbar(dev);
 
+	destroy_workqueue(dev_priv->dp_wq);
 	destroy_workqueue(dev_priv->wq);
 	pm_qos_remove_request(&dev_priv->pm_qos);
 
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 7d6acb4..b3b5864c 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1468,6 +1468,18 @@  struct drm_i915_private {
 
 	struct i915_runtime_pm pm;
 
+	struct intel_digital_port *hpd_irq_port[I915_MAX_PORTS];
+	u32 hpd_port;
+	struct work_struct dig_port_work;
+	/*
+	 * if we get a HPD irq from DP and a HPD irq from non-DP
+	 * the non-DP HPD could block the workqueue on a mode config
+	 * mutex getting, that userspace may have taken. However
+	 * userspace is waiting on the DP workqueue to run which is
+	 * blocked behind the non-DP one.
+	 */
+	struct workqueue_struct *dp_wq;
+
 	/* Old dri1 support infrastructure, beware the dragons ya fools entering
 	 * here! */
 	struct i915_dri1_state dri1;
@@ -1999,6 +2011,8 @@  i915_disable_pipestat(struct drm_i915_private *dev_priv, enum pipe pipe,
 
 void valleyview_enable_display_irqs(struct drm_i915_private *dev_priv);
 void valleyview_disable_display_irqs(struct drm_i915_private *dev_priv);
+bool intel_hpd_irq_event(struct drm_device *dev,
+			 struct drm_connector *connector);
 
 /* i915_gem.c */
 int i915_gem_init_ioctl(struct drm_device *dev, void *data,
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 5852dee..0b16d41 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -963,8 +963,8 @@  static int i915_get_vblank_timestamp(struct drm_device *dev, int pipe,
 						     &to_intel_crtc(crtc)->config.adjusted_mode);
 }
 
-static bool intel_hpd_irq_event(struct drm_device *dev,
-				struct drm_connector *connector)
+bool intel_hpd_irq_event(struct drm_device *dev,
+			 struct drm_connector *connector)
 {
 	enum drm_connector_status old_status;
 
@@ -984,6 +984,71 @@  static bool intel_hpd_irq_event(struct drm_device *dev,
 	return true;
 }
 
+static int port_to_hotplug_shift(enum port port)
+{
+	switch (port) {
+	case PORT_A:
+	case PORT_E:
+	default:
+		return -1;
+	case PORT_B:
+		return 0;
+	case PORT_C:
+		return 8;
+	case PORT_D:
+		return 16;
+	}
+}
+static void i915_digport_work_func(struct work_struct *work)
+{
+	struct drm_i915_private *dev_priv =
+		container_of(work, struct drm_i915_private, dig_port_work);
+	unsigned long irqflags;
+	u32 port_bits;
+	struct intel_digital_port *digport;
+	int i, ret;
+	u32 old_bits = 0;
+	u32 hotplug_reg, hpshift;
+	bool long_hpd = false;
+	spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
+	port_bits = dev_priv->hpd_port;
+	dev_priv->hpd_port = 0;
+
+	hotplug_reg = I915_READ(PCH_PORT_HOTPLUG);
+	I915_WRITE(PCH_PORT_HOTPLUG, hotplug_reg);
+
+	spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
+
+	for (i = 0; i < I915_MAX_PORTS; i++) {
+		if (port_bits & (1 << i)) {
+			digport = dev_priv->hpd_irq_port[i];
+
+			hpshift = port_to_hotplug_shift(i);
+
+			/* if we have no HPD bits for this */
+			if (!((hotplug_reg >> hpshift) & PORTB_HOTPLUG_STATUS_MASK)) {
+				DRM_DEBUG_KMS("got not regs for port %d %08x\n", i, hotplug_reg);
+				continue;
+			}
+
+			long_hpd = (hotplug_reg >> hpshift) & PORTB_HOTPLUG_LONG_DETECT;
+
+			ret = intel_dp_handle_hpd_irq(digport, long_hpd);
+			if (ret == 1) {
+				/* if we get 1 fallback to old school hpd */
+				old_bits |= (1 << digport->base.hpd_pin);
+			}
+		}
+	}
+
+	if (old_bits) {
+		spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
+		dev_priv->hpd_event_bits = old_bits;
+		spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
+		schedule_work(&dev_priv->hotplug_work);
+	}
+}
+
 /*
  * Handle hotplug events outside the interrupt handler proper.
  */
@@ -1381,14 +1446,29 @@  static irqreturn_t gen8_gt_irq_handler(struct drm_device *dev,
 #define HPD_STORM_DETECT_PERIOD 1000
 #define HPD_STORM_THRESHOLD 5
 
+static inline enum port get_port_from_pin(enum hpd_pin pin)
+{
+	switch (pin) {
+	case HPD_PORT_B:
+		return PORT_B;
+	case HPD_PORT_C:
+		return PORT_C;
+	case HPD_PORT_D:
+		return PORT_D;
+	default:
+		return PORT_A; /* no hpd */
+	}
+}
+
 static inline void intel_hpd_irq_handler(struct drm_device *dev,
 					 u32 hotplug_trigger,
 					 const u32 *hpd)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	int i;
+	enum port port;
 	bool storm_detected = false;
-
+	bool queue_dig = false, queue_hp = false;
 	if (!hotplug_trigger)
 		return;
 
@@ -1397,6 +1477,19 @@  static inline void intel_hpd_irq_handler(struct drm_device *dev,
 
 	spin_lock(&dev_priv->irq_lock);
 	for (i = 1; i < HPD_NUM_PINS; i++) {
+		if (!(hpd[i] & hotplug_trigger))
+			continue;
+
+		port = get_port_from_pin(i);
+		if (port && dev_priv->hpd_irq_port[port]) {
+			DRM_DEBUG_DRIVER("digital hpd port %d\n", port);
+			dev_priv->hpd_port |= (1 << port);
+			hotplug_trigger &= ~hpd[i];
+			queue_dig = true;
+		}
+	}
+
+	for (i = 1; i < HPD_NUM_PINS; i++) {
 
 		if (hpd[i] & hotplug_trigger &&
 		    dev_priv->hpd_stats[i].hpd_mark == HPD_DISABLED) {
@@ -1418,6 +1511,7 @@  static inline void intel_hpd_irq_handler(struct drm_device *dev,
 			continue;
 
 		dev_priv->hpd_event_bits |= (1 << i);
+		queue_hp = true;
 		if (!time_in_range(jiffies, dev_priv->hpd_stats[i].hpd_last_jiffies,
 				   dev_priv->hpd_stats[i].hpd_last_jiffies
 				   + msecs_to_jiffies(HPD_STORM_DETECT_PERIOD))) {
@@ -1446,7 +1540,10 @@  static inline void intel_hpd_irq_handler(struct drm_device *dev,
 	 * queue for otherwise the flush_work in the pageflip code will
 	 * deadlock.
 	 */
-	schedule_work(&dev_priv->hotplug_work);
+	if (queue_dig)
+		queue_work(dev_priv->dp_wq, &dev_priv->dig_port_work);
+	if (queue_hp)
+		schedule_work(&dev_priv->hotplug_work);
 }
 
 static void gmbus_irq_handler(struct drm_device *dev)
@@ -4014,6 +4111,7 @@  void intel_irq_init(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
 
+	INIT_WORK(&dev_priv->dig_port_work, i915_digport_work_func);
 	INIT_WORK(&dev_priv->hotplug_work, i915_hotplug_work_func);
 	INIT_WORK(&dev_priv->gpu_error.work, i915_error_work_func);
 	INIT_WORK(&dev_priv->rps.work, gen6_pm_rps_work);
diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
index a5b8b76..a8728d1 100644
--- a/drivers/gpu/drm/i915/intel_ddi.c
+++ b/drivers/gpu/drm/i915/intel_ddi.c
@@ -116,7 +116,10 @@  enum port intel_ddi_get_encoder_port(struct intel_encoder *intel_encoder)
 	struct drm_encoder *encoder = &intel_encoder->base;
 	int type = intel_encoder->type;
 
-	if (type == INTEL_OUTPUT_DISPLAYPORT || type == INTEL_OUTPUT_EDP ||
+	if (type == INTEL_OUTPUT_DP_MST) {
+		struct intel_digital_port *intel_dig_port = enc_to_mst(encoder)->primary;
+		return intel_dig_port->port;
+	} else if (type == INTEL_OUTPUT_DISPLAYPORT || type == INTEL_OUTPUT_EDP ||
 	    type == INTEL_OUTPUT_HDMI || type == INTEL_OUTPUT_UNKNOWN) {
 		struct intel_digital_port *intel_dig_port =
 			enc_to_dig_port(encoder);
@@ -211,6 +214,19 @@  void intel_prepare_ddi(struct drm_device *dev)
 		intel_prepare_ddi_buffers(dev, port);
 }
 
+void intel_ddi_force_act(struct intel_encoder *encoder, bool state)
+{
+	struct drm_i915_private *dev_priv = encoder->base.dev->dev_private;
+	enum port port = intel_ddi_get_encoder_port(encoder);
+	u32 val;
+	val = I915_READ(DP_TP_CTL(port));
+	if (state == true)
+		val |= DP_TP_CTL_FORCE_ACT;
+	else
+		val &= ~DP_TP_CTL_FORCE_ACT;
+	I915_WRITE(DP_TP_CTL(port), val);
+}
+
 static const long hsw_ddi_buf_ctl_values[] = {
 	DDI_BUF_EMP_400MV_0DB_HSW,
 	DDI_BUF_EMP_400MV_3_5DB_HSW,
@@ -673,8 +689,8 @@  static int intel_ddi_calc_wrpll_link(struct drm_i915_private *dev_priv,
 	return (refclk * n * 100) / (p * r);
 }
 
-static void intel_ddi_clock_get(struct intel_encoder *encoder,
-				struct intel_crtc_config *pipe_config)
+void intel_ddi_clock_get(struct intel_encoder *encoder,
+			 struct intel_crtc_config *pipe_config)
 {
 	struct drm_i915_private *dev_priv = encoder->base.dev->dev_private;
 	enum port port = intel_ddi_get_encoder_port(encoder);
@@ -795,6 +811,20 @@  intel_ddi_calculate_wrpll(int clock /* in Hz */,
 	*r2_out = best.r2;
 }
 
+static int link_bw_to_pll_sel(int link_bw)
+{
+	switch (link_bw) {
+	case DP_LINK_BW_1_62:
+		return PORT_CLK_SEL_LCPLL_810;
+	case DP_LINK_BW_2_7:
+		return PORT_CLK_SEL_LCPLL_1350;
+	case DP_LINK_BW_5_4:
+		return PORT_CLK_SEL_LCPLL_2700;
+	default:
+		return -1;
+	}
+}
+
 /*
  * Tries to find a PLL for the CRTC. If it finds, it increases the refcount and
  * stores it in intel_crtc->ddi_pll_sel, so other mode sets won't be able to
@@ -814,20 +844,19 @@  bool intel_ddi_pll_select(struct intel_crtc *intel_crtc)
 
 	intel_ddi_put_crtc_pll(crtc);
 
-	if (type == INTEL_OUTPUT_DISPLAYPORT || type == INTEL_OUTPUT_EDP) {
+	if (type == INTEL_OUTPUT_DP_MST) {
+		struct intel_dp_mst_encoder *intel_mst = enc_to_mst(encoder);
+		intel_crtc->ddi_pll_sel = link_bw_to_pll_sel(intel_mst->primary->dp.link_bw);
+		if (intel_crtc->ddi_pll_sel == -1) {
+			DRM_ERROR("Link bandwidth %d unsupported\n",
+				  intel_mst->primary->dp.link_bw);
+			return false;
+		}
+	} else if (type == INTEL_OUTPUT_DISPLAYPORT || type == INTEL_OUTPUT_EDP) {
 		struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
 
-		switch (intel_dp->link_bw) {
-		case DP_LINK_BW_1_62:
-			intel_crtc->ddi_pll_sel = PORT_CLK_SEL_LCPLL_810;
-			break;
-		case DP_LINK_BW_2_7:
-			intel_crtc->ddi_pll_sel = PORT_CLK_SEL_LCPLL_1350;
-			break;
-		case DP_LINK_BW_5_4:
-			intel_crtc->ddi_pll_sel = PORT_CLK_SEL_LCPLL_2700;
-			break;
-		default:
+		intel_crtc->ddi_pll_sel = link_bw_to_pll_sel(intel_dp->link_bw);
+		if (intel_crtc->ddi_pll_sel == -1) {
 			DRM_ERROR("Link bandwidth %d unsupported\n",
 				  intel_dp->link_bw);
 			return false;
@@ -981,8 +1010,7 @@  void intel_ddi_set_pipe_settings(struct drm_crtc *crtc)
 	int type = intel_encoder->type;
 	uint32_t temp;
 
-	if (type == INTEL_OUTPUT_DISPLAYPORT || type == INTEL_OUTPUT_EDP) {
-
+	if (type == INTEL_OUTPUT_DISPLAYPORT || type == INTEL_OUTPUT_EDP || type == INTEL_OUTPUT_DP_MST) {
 		temp = TRANS_MSA_SYNC_CLK;
 		switch (intel_crtc->config.pipe_bpp) {
 		case 18:
@@ -1004,6 +1032,21 @@  void intel_ddi_set_pipe_settings(struct drm_crtc *crtc)
 	}
 }
 
+void intel_ddi_set_vc_payload_alloc(struct drm_crtc *crtc, bool state)
+{
+	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
+	struct drm_device *dev = crtc->dev;
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	enum transcoder cpu_transcoder = intel_crtc->config.cpu_transcoder;
+	uint32_t temp;
+	temp = I915_READ(TRANS_DDI_FUNC_CTL(cpu_transcoder));
+	if (state == true)
+		temp |= TRANS_DDI_DP_VC_PAYLOAD_ALLOC;
+	else
+		temp &= ~TRANS_DDI_DP_VC_PAYLOAD_ALLOC;
+	I915_WRITE(TRANS_DDI_FUNC_CTL(cpu_transcoder), temp);
+}
+
 void intel_ddi_enable_transcoder_func(struct drm_crtc *crtc)
 {
 	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
@@ -1083,7 +1126,19 @@  void intel_ddi_enable_transcoder_func(struct drm_crtc *crtc)
 		   type == INTEL_OUTPUT_EDP) {
 		struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
 
-		temp |= TRANS_DDI_MODE_SELECT_DP_SST;
+		if (intel_dp->is_mst) {
+			temp |= TRANS_DDI_MODE_SELECT_DP_MST;
+		} else
+			temp |= TRANS_DDI_MODE_SELECT_DP_SST;
+
+		temp |= DDI_PORT_WIDTH(intel_dp->lane_count);
+	} else if (type == INTEL_OUTPUT_DP_MST) {
+		struct intel_dp *intel_dp = &enc_to_mst(encoder)->primary->dp;
+
+		if (intel_dp->is_mst) {
+			temp |= TRANS_DDI_MODE_SELECT_DP_MST;
+		} else
+			temp |= TRANS_DDI_MODE_SELECT_DP_SST;
 
 		temp |= DDI_PORT_WIDTH(intel_dp->lane_count);
 	} else {
@@ -1100,7 +1155,7 @@  void intel_ddi_disable_transcoder_func(struct drm_i915_private *dev_priv,
 	uint32_t reg = TRANS_DDI_FUNC_CTL(cpu_transcoder);
 	uint32_t val = I915_READ(reg);
 
-	val &= ~(TRANS_DDI_FUNC_ENABLE | TRANS_DDI_PORT_MASK);
+	val &= ~(TRANS_DDI_FUNC_ENABLE | TRANS_DDI_PORT_MASK | TRANS_DDI_DP_VC_PAYLOAD_ALLOC);
 	val |= TRANS_DDI_PORT_NONE;
 	I915_WRITE(reg, val);
 }
@@ -1160,6 +1215,11 @@  bool intel_ddi_get_hw_state(struct intel_encoder *encoder,
 	u32 tmp;
 	int i;
 
+	if (encoder->type == INTEL_OUTPUT_DISPLAYPORT) {
+		if (enc_to_intel_dp(&encoder->base)->is_mst)
+			return false;
+	}
+
 	power_domain = intel_display_port_power_domain(encoder);
 	if (!intel_display_power_enabled(dev_priv, power_domain))
 		return false;
@@ -1498,10 +1558,15 @@  void intel_ddi_prepare_link_retrain(struct drm_encoder *encoder)
 			intel_wait_ddi_buf_idle(dev_priv, port);
 	}
 
-	val = DP_TP_CTL_ENABLE | DP_TP_CTL_MODE_SST |
+	val = DP_TP_CTL_ENABLE |
 	      DP_TP_CTL_LINK_TRAIN_PAT1 | DP_TP_CTL_SCRAMBLE_DISABLE;
-	if (drm_dp_enhanced_frame_cap(intel_dp->dpcd))
-		val |= DP_TP_CTL_ENHANCED_FRAME_ENABLE;
+	if (intel_dp->is_mst)
+		val |= DP_TP_CTL_MODE_MST;
+	else {
+		val |= DP_TP_CTL_MODE_SST;
+		if (drm_dp_enhanced_frame_cap(intel_dp->dpcd))
+			val |= DP_TP_CTL_ENHANCED_FRAME_ENABLE;
+	}
 	I915_WRITE(DP_TP_CTL(port), val);
 	POSTING_READ(DP_TP_CTL(port));
 
@@ -1732,6 +1797,8 @@  void intel_ddi_init(struct drm_device *dev, enum port port)
 	intel_encoder->cloneable = 0;
 	intel_encoder->hot_plug = intel_ddi_hot_plug;
 
+	dev_priv->hpd_irq_port[port] = intel_dig_port;
+
 	if (init_dp)
 		dp_connector = intel_ddi_init_dp_connector(intel_dig_port);
 
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 75b2aaf..dfcc78e 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -56,6 +56,14 @@  static int intel_framebuffer_init(struct drm_device *dev,
 				  struct drm_mode_fb_cmd2 *mode_cmd,
 				  struct drm_i915_gem_object *obj);
 
+static struct intel_encoder *intel_find_encoder(struct intel_connector *connector, int pipe)
+{
+	if (!connector->mst_port)
+		return connector->encoder;
+	else
+		return &connector->mst_port->mst_encoders[pipe]->base;
+}
+
 typedef struct {
 	int	min, max;
 } intel_range_t;
@@ -3821,6 +3829,9 @@  static void haswell_crtc_enable(struct drm_crtc *crtc)
 	if (intel_crtc->config.has_pch_encoder)
 		lpt_pch_enable(crtc);
 
+	if (intel_crtc->config.dp_encoder_is_mst)
+		intel_ddi_set_vc_payload_alloc(crtc, true);
+
 	for_each_encoder_on_crtc(dev, crtc, encoder) {
 		encoder->enable(encoder);
 		intel_opregion_notify_encoder(encoder, true);
@@ -3869,6 +3880,9 @@  static void ironlake_crtc_disable(struct drm_crtc *crtc)
 
 	intel_disable_pipe(dev_priv, pipe);
 
+	if (intel_crtc->config.dp_encoder_is_mst)
+		intel_ddi_set_vc_payload_alloc(crtc, false);
+
 	ironlake_pfit_disable(intel_crtc);
 
 	for_each_encoder_on_crtc(dev, crtc, encoder)
@@ -4038,6 +4052,23 @@  static void i9xx_pfit_enable(struct intel_crtc *crtc)
 	for ((domain) = 0; (domain) < POWER_DOMAIN_NUM; (domain)++)	\
 		if ((1 << (domain)) & (mask))
 
+enum intel_display_power_domain port_to_power_domain(enum port port)
+{
+	switch (port) {
+	case PORT_A:
+		return POWER_DOMAIN_PORT_DDI_A_4_LANES;
+	case PORT_B:
+		return POWER_DOMAIN_PORT_DDI_B_4_LANES;
+	case PORT_C:
+		return POWER_DOMAIN_PORT_DDI_C_4_LANES;
+	case PORT_D:
+		return POWER_DOMAIN_PORT_DDI_D_4_LANES;
+	default:
+		WARN_ON_ONCE(1);
+		return POWER_DOMAIN_PORT_OTHER;
+	}
+}
+
 enum intel_display_power_domain
 intel_display_port_power_domain(struct intel_encoder *intel_encoder)
 {
@@ -4052,19 +4083,10 @@  intel_display_port_power_domain(struct intel_encoder *intel_encoder)
 	case INTEL_OUTPUT_HDMI:
 	case INTEL_OUTPUT_EDP:
 		intel_dig_port = enc_to_dig_port(&intel_encoder->base);
-		switch (intel_dig_port->port) {
-		case PORT_A:
-			return POWER_DOMAIN_PORT_DDI_A_4_LANES;
-		case PORT_B:
-			return POWER_DOMAIN_PORT_DDI_B_4_LANES;
-		case PORT_C:
-			return POWER_DOMAIN_PORT_DDI_C_4_LANES;
-		case PORT_D:
-			return POWER_DOMAIN_PORT_DDI_D_4_LANES;
-		default:
-			WARN_ON_ONCE(1);
-			return POWER_DOMAIN_PORT_OTHER;
-		}
+		return port_to_power_domain(intel_dig_port->port);
+	case INTEL_OUTPUT_DP_MST:
+		intel_dig_port = enc_to_mst(&intel_encoder->base)->primary;
+		return port_to_power_domain(intel_dig_port->port);
 	case INTEL_OUTPUT_ANALOG:
 		return POWER_DOMAIN_PORT_CRT;
 	case INTEL_OUTPUT_DSI:
@@ -10203,7 +10225,7 @@  intel_modeset_stage_output_state(struct drm_device *dev,
 		 * for them. */
 		for (ro = 0; ro < set->num_connectors; ro++) {
 			if (set->connectors[ro] == &connector->base) {
-				connector->new_encoder = connector->encoder;
+				connector->new_encoder = intel_find_encoder(connector, to_intel_crtc(set->crtc)->pipe);
 				break;
 			}
 		}
@@ -10249,7 +10271,7 @@  intel_modeset_stage_output_state(struct drm_device *dev,
 					 new_crtc)) {
 			return -EINVAL;
 		}
-		connector->encoder->new_crtc = to_intel_crtc(new_crtc);
+		connector->new_encoder->new_crtc = to_intel_crtc(new_crtc);
 
 		DRM_DEBUG_KMS("[CONNECTOR:%d:%s] to [CRTC:%d]\n",
 			connector->base.base.id,
@@ -10283,7 +10305,12 @@  intel_modeset_stage_output_state(struct drm_device *dev,
 		}
 	}
 	/* Now we've also updated encoder->new_crtc for all encoders. */
-
+	list_for_each_entry(connector, &dev->mode_config.connector_list,
+			    base.head) {
+		if (connector->new_encoder)
+			if (connector->new_encoder != connector->encoder)
+				connector->encoder = connector->new_encoder;
+	}
 	list_for_each_entry(crtc, &dev->mode_config.crtc_list,
 			    base.head) {
 		crtc->new_enabled = false;
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 44df493..e1bd017 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -701,8 +701,9 @@  intel_dp_connector_unregister(struct intel_connector *intel_connector)
 {
 	struct intel_dp *intel_dp = intel_attached_dp(&intel_connector->base);
 
-	sysfs_remove_link(&intel_connector->base.kdev->kobj,
-			  intel_dp->aux.ddc.dev.kobj.name);
+	if (!intel_connector->mst_port)
+		sysfs_remove_link(&intel_connector->base.kdev->kobj,
+				  intel_dp->aux.ddc.dev.kobj.name);
 	intel_connector_unregister(intel_connector);
 }
 
@@ -2892,6 +2893,33 @@  intel_dp_probe_oui(struct intel_dp *intel_dp)
 	edp_panel_vdd_off(intel_dp, false);
 }
 
+static bool
+intel_dp_probe_mst(struct intel_dp *intel_dp)
+{
+	u8 buf[1];
+
+	if (!intel_dp->can_mst)
+		return false;
+
+	if (intel_dp->dpcd[DP_DPCD_REV] < 0x12)
+		return false;
+
+	_edp_panel_vdd_on(intel_dp);
+	if (intel_dp_dpcd_read_wake(&intel_dp->aux, DP_MSTM_CAP, buf, 1)) {
+		if (buf[0] & DP_MST_CAP) {
+			DRM_DEBUG_KMS("Sink is MST capable\n");
+			intel_dp->is_mst = true;
+		} else {
+			DRM_DEBUG_KMS("Sink is not MST capable\n");
+			intel_dp->is_mst = false;
+		}
+	}
+	edp_panel_vdd_off(intel_dp, false);
+
+	drm_dp_mst_topology_mgr_set_mst(&intel_dp->mst_mgr, intel_dp->is_mst);
+	return intel_dp->is_mst;
+}
+
 int intel_dp_sink_crc(struct intel_dp *intel_dp, u8 *crc)
 {
 	struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
@@ -2929,6 +2957,20 @@  intel_dp_get_sink_irq(struct intel_dp *intel_dp, u8 *sink_irq_vector)
 				       sink_irq_vector, 1) == 1;
 }
 
+static bool
+intel_dp_get_sink_irq_esi(struct intel_dp *intel_dp, u8 *sink_irq_vector)
+{
+	int ret;
+
+	ret = intel_dp_dpcd_read_wake(&intel_dp->aux,
+					     DP_SINK_COUNT_ESI,
+					     sink_irq_vector, 4);
+	if (ret != 4)
+		return false;
+
+	return true;
+}
+
 static void
 intel_dp_handle_test_request(struct intel_dp *intel_dp)
 {
@@ -2944,6 +2986,65 @@  intel_dp_handle_test_request(struct intel_dp *intel_dp)
  *  3. Use Link Training from 2.5.3.3 and 3.5.1.3
  *  4. Check link status on receipt of hot-plug interrupt
  */
+static int
+intel_dp_check_mst_status(struct intel_dp *intel_dp)
+{
+	int send_event = 0;
+	bool bret;
+	if (intel_dp->is_mst) {
+		u8 esi[4] = { 0 };
+		int ret = 0;
+		int retry;
+
+		mutex_lock(&intel_dp->mst_mgr.aux_lock);
+		bret = intel_dp_get_sink_irq_esi(intel_dp, esi);
+		mutex_unlock(&intel_dp->mst_mgr.aux_lock);
+	go_again:
+		if (bret == true) {
+			DRM_DEBUG_KMS("got esi %02x %02x %02x\n", esi[0], esi[1], esi[2]);
+			if (esi[1] & (DP_UP_REQ_MSG_RDY | DP_DOWN_REP_MSG_RDY))  {
+				ret = drm_dp_mst_hpd_irq(&intel_dp->mst_mgr, esi[1]);
+				if (ret == 1)
+					send_event = 1;
+			} else
+				ret = 0;
+			send_event |= ret;
+			mutex_lock(&intel_dp->mst_mgr.aux_lock);
+			for (retry = 0; retry < 3; retry++) {
+				int wret;
+				wret = drm_dp_dpcd_write(&intel_dp->aux,
+							DP_SINK_COUNT_ESI+1,
+							&esi[1], 3);
+				if (wret == 3) {
+					break;
+				}
+			}
+			mutex_unlock(&intel_dp->mst_mgr.aux_lock);
+
+			mutex_lock(&intel_dp->mst_mgr.aux_lock);
+			bret = intel_dp_get_sink_irq_esi(intel_dp, esi);
+			mutex_unlock(&intel_dp->mst_mgr.aux_lock);
+			if (bret == true) {
+				DRM_DEBUG_KMS("got esi2 %02x %02x %02x\n", esi[0], esi[1], esi[2]);
+				if (esi[1] & (DP_UP_REQ_MSG_RDY | DP_DOWN_REP_MSG_RDY))  {
+					goto go_again;
+				}
+			}
+
+			if (ret == 0 && send_event)
+				return 1;
+			return ret;
+		} else {
+			struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
+			DRM_DEBUG_KMS("failed to get ESI - device may have failed\n");
+			intel_dp->is_mst = false;
+			drm_dp_mst_topology_mgr_set_mst(&intel_dp->mst_mgr, intel_dp->is_mst);
+			/* send a hotplug event */
+			drm_sysfs_hotplug_event(intel_dig_port->base.base.dev);
+		}
+	}
+	return -EINVAL;
+}
 
 void
 intel_dp_check_link_status(struct intel_dp *intel_dp)
@@ -3163,6 +3264,7 @@  intel_dp_detect(struct drm_connector *connector, bool force)
 	enum drm_connector_status status;
 	enum intel_display_power_domain power_domain;
 	struct edid *edid = NULL;
+	bool ret;
 
 	intel_runtime_pm_get(dev_priv);
 
@@ -3172,6 +3274,12 @@  intel_dp_detect(struct drm_connector *connector, bool force)
 	DRM_DEBUG_KMS("[CONNECTOR:%d:%s]\n",
 		      connector->base.id, drm_get_connector_name(connector));
 
+	if (intel_dp->is_mst) {
+		/* MST devices are disconnected from a monitor POV */
+		status = connector_status_disconnected;
+		goto out;
+	}
+
 	intel_dp->has_audio = false;
 
 	if (HAS_PCH_SPLIT(dev))
@@ -3184,6 +3292,16 @@  intel_dp_detect(struct drm_connector *connector, bool force)
 
 	intel_dp_probe_oui(intel_dp);
 
+	ret = intel_dp_probe_mst(intel_dp);
+	if (ret) {
+		/* if we are in MST mode then this connector
+		   won't appear connected or have anything with EDID on it */
+		if (intel_encoder->type != INTEL_OUTPUT_EDP)
+			intel_encoder->type = INTEL_OUTPUT_DISPLAYPORT;
+		status = connector_status_disconnected;
+		goto out;
+	}
+
 	if (intel_dp->force_audio != HDMI_AUDIO_AUTO) {
 		intel_dp->has_audio = (intel_dp->force_audio == HDMI_AUDIO_ON);
 	} else {
@@ -3379,6 +3497,7 @@  void intel_dp_encoder_destroy(struct drm_encoder *encoder)
 	struct drm_device *dev = intel_dp_to_dev(intel_dp);
 
 	drm_dp_aux_unregister_i2c_bus(&intel_dp->aux);
+	intel_dp_mst_encoder_cleanup(intel_dig_port);
 	drm_encoder_cleanup(encoder);
 	if (is_edp(intel_dp)) {
 		cancel_delayed_work_sync(&intel_dp->panel_vdd_work);
@@ -3463,7 +3582,7 @@  bool intel_dp_is_edp(struct drm_device *dev, enum port port)
 	return false;
 }
 
-static void
+void
 intel_dp_add_properties(struct intel_dp *intel_dp, struct drm_connector *connector)
 {
 	struct intel_connector *intel_connector = to_intel_connector(connector);
@@ -3959,6 +4078,13 @@  intel_dp_init_connector(struct intel_digital_port *intel_dig_port,
 
 	intel_dp->psr_setup_done = false;
 
+	/* init MST on ports that can support it */
+	if (IS_HASWELL(dev) || IS_BROADWELL(dev)) {
+		if (port == PORT_B || port == PORT_C || port == PORT_D) {
+			intel_dp_mst_encoder_init(intel_dig_port, intel_connector->base.base.id);
+		}
+	}
+
 	if (!intel_edp_init_connector(intel_dp, intel_connector, &power_seq)) {
 		drm_dp_aux_unregister_i2c_bus(&intel_dp->aux);
 		if (is_edp(intel_dp)) {
@@ -3989,6 +4115,7 @@  intel_dp_init_connector(struct intel_digital_port *intel_dig_port,
 void
 intel_dp_init(struct drm_device *dev, int output_reg, enum port port)
 {
+	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct intel_digital_port *intel_dig_port;
 	struct intel_encoder *intel_encoder;
 	struct drm_encoder *encoder;
@@ -4029,6 +4156,10 @@  intel_dp_init(struct drm_device *dev, int output_reg, enum port port)
 	intel_dig_port->port = port;
 	intel_dig_port->dp.output_reg = output_reg;
 
+	/* for now only use new IRQ handling for MST capable ports */
+	if (intel_dig_port->dp.can_mst)
+		dev_priv->hpd_irq_port[port] = intel_dig_port;
+
 	intel_encoder->type = INTEL_OUTPUT_DISPLAYPORT;
 	intel_encoder->crtc_mask = (1 << 0) | (1 << 1) | (1 << 2);
 	intel_encoder->cloneable = 0;
@@ -4040,3 +4171,79 @@  intel_dp_init(struct drm_device *dev, int output_reg, enum port port)
 		kfree(intel_connector);
 	}
 }
+
+/*
+ * Handle DP IRQ close to spec recommendations
+ * Use hw to detect long vs short pulses
+ *
+ * If we get a long pulse - we need to read DPCD first
+ * If we get a short pulse - we need to check link irq/status
+ * returning 1 causes the old detect to happen for HDMI
+ */
+int intel_dp_handle_hpd_irq(struct intel_digital_port *intel_dig_port,
+			    bool hpd_long)
+{
+	struct intel_dp *intel_dp = &intel_dig_port->dp;
+	struct drm_device *dev = intel_dig_port->base.base.dev;
+	struct drm_mode_config *mode_config = &dev->mode_config;
+	struct drm_connector *connector;
+	struct intel_connector *intel_connector;
+	bool changed = false;
+	int ret;
+
+	if (!intel_dp->output_reg)
+		return 1;
+
+	DRM_DEBUG_KMS("got hpd irq on port %d - %s\n", intel_dig_port->port,
+		      hpd_long ? "long" : "short");
+	/* we have to re-read DPCD only on a long irq */
+	if (hpd_long) {
+		if (!intel_dp_get_dpcd(intel_dp))
+			goto mst_fail;
+
+		intel_dp_probe_oui(intel_dp);
+
+		if (!intel_dp_probe_mst(intel_dp))
+			goto mst_fail;
+	}
+
+	if (intel_dp->is_mst) {
+		ret = intel_dp_check_mst_status(intel_dp);
+		if (ret == -EINVAL)
+			return 1;
+	} else {
+		intel_dp_check_link_status(intel_dp);
+		return 1;
+	}
+
+	if (ret == 1) {
+		mutex_lock(&mode_config->mutex);
+
+		/* send the something changed event for the correct port */
+		list_for_each_entry(connector, &mode_config->connector_list, head) {
+			intel_connector = to_intel_connector(connector);
+			if (!intel_connector->mst_port)
+				continue;
+
+			if (intel_connector->mst_port != intel_dp)
+				continue;
+
+			if (intel_hpd_irq_event(dev, connector))
+				changed = true;
+		}
+		mutex_unlock(&mode_config->mutex);
+		if (changed)
+			drm_kms_helper_hotplug_event(dev);
+	}
+	return 0;
+
+mst_fail:
+	/* if we were in MST mode, and device is not there get out of MST mode */
+	if (intel_dp->is_mst) {
+		DRM_DEBUG_KMS("failed to get ESI - device may have failed\n");
+		intel_dp->is_mst = false;
+		drm_dp_mst_topology_mgr_set_mst(&intel_dp->mst_mgr, intel_dp->is_mst);
+		drm_sysfs_hotplug_event(dev);
+	}
+	return 1;
+}
diff --git a/drivers/gpu/drm/i915/intel_dp_mst.c b/drivers/gpu/drm/i915/intel_dp_mst.c
new file mode 100644
index 0000000..a656c22
--- /dev/null
+++ b/drivers/gpu/drm/i915/intel_dp_mst.c
@@ -0,0 +1,530 @@ 
+/*
+ * Copyright © 2008 Intel Corporation
+ *             2014 Red Hat Inc.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ *
+ */
+
+#include <drm/drmP.h>
+#include "i915_drv.h"
+#include "intel_drv.h"
+#include <drm/drm_crtc_helper.h>
+#include <drm/drm_edid.h>
+
+bool
+intel_dp_mst_compute_config(struct intel_encoder *encoder,
+			    struct intel_crtc_config *pipe_config)
+{
+	struct intel_dp_mst_encoder *intel_mst = enc_to_mst(&encoder->base);
+	struct intel_digital_port *intel_dig_port = intel_mst->primary;
+	struct intel_dp *intel_dp = &intel_dig_port->dp;
+	struct drm_device *dev = encoder->base.dev;
+	int bpp;
+	int lane_count, slots;
+	struct drm_display_mode *adjusted_mode = &pipe_config->adjusted_mode;
+	struct intel_connector *found = NULL, *intel_connector;
+	int mst_pbn;
+
+	pipe_config->dp_encoder_is_mst = true;
+	pipe_config->has_pch_encoder = false;
+	pipe_config->has_dp_encoder = true;
+	bpp = 24;
+	lane_count = 4;
+	intel_dp->link_bw = DP_LINK_BW_5_4;
+	intel_dp->lane_count = lane_count;
+
+	pipe_config->pipe_bpp = 24;
+	pipe_config->port_clock = drm_dp_bw_code_to_link_rate(intel_dp->link_bw);
+
+	list_for_each_entry(intel_connector, &dev->mode_config.connector_list, base.head) {
+		if (intel_connector->new_encoder == encoder) {
+			found = intel_connector;
+			break;
+		}
+	}
+
+	if (!found) {
+		DRM_ERROR("can't find connector\n");
+		return false;
+	}
+
+	mst_pbn = drm_dp_calc_pbn_mode(adjusted_mode->clock, bpp);
+
+	pipe_config->pbn = mst_pbn;
+	slots = drm_dp_find_vcpi_slots(&intel_dp->mst_mgr, mst_pbn);
+
+	intel_link_compute_m_n(bpp, lane_count,
+			       adjusted_mode->crtc_clock,
+			       pipe_config->port_clock,
+			       &pipe_config->dp_m_n);
+
+	pipe_config->dp_m_n.tu = slots;
+	return true;
+
+}
+
+static void intel_dp_mst_mode_set(struct intel_encoder *encoder)
+{
+	struct intel_dp_mst_encoder *intel_mst = enc_to_mst(&encoder->base);
+	struct intel_digital_port *intel_dig_port = intel_mst->primary;
+
+	intel_ddi_mode_set_dp(&intel_dig_port->base);
+}
+
+static void intel_mst_disable_dp(struct intel_encoder *encoder)
+{
+	struct intel_dp_mst_encoder *intel_mst = enc_to_mst(&encoder->base);
+	struct intel_connector *found = NULL, *intel_connector;
+	struct intel_digital_port *intel_dig_port = intel_mst->primary;
+	struct intel_dp *intel_dp = &intel_dig_port->dp;
+	struct drm_device *dev = encoder->base.dev;
+	int ret;
+
+	DRM_DEBUG_KMS("%d\n", intel_dp->active_mst_links);
+	list_for_each_entry(intel_connector, &dev->mode_config.connector_list, base.head) {
+		if (intel_connector->encoder == encoder) {
+			found = intel_connector;
+			break;
+		}
+	}
+
+	if (!found)
+		return;
+
+	drm_dp_mst_reset_vcpi_slots(&intel_dp->mst_mgr, found->port);
+
+	ret = drm_dp_update_payload_part1(&intel_dp->mst_mgr);
+	if (ret) {
+		DRM_ERROR("failed to update payload %d\n", ret);
+	}
+}
+
+static void intel_mst_post_disable_dp(struct intel_encoder *encoder)
+{
+	struct intel_dp_mst_encoder *intel_mst = enc_to_mst(&encoder->base);
+	struct intel_digital_port *intel_dig_port = intel_mst->primary;
+	struct intel_dp *intel_dp = &intel_dig_port->dp;
+	struct intel_connector *found = NULL, *intel_connector;
+	struct drm_device *dev = encoder->base.dev;
+	int ret;
+	DRM_DEBUG_KMS("%d\n", intel_dp->active_mst_links);
+
+	list_for_each_entry(intel_connector, &dev->mode_config.connector_list, base.head) {
+		if (intel_connector->encoder == encoder) {
+			found = intel_connector;
+			break;
+		}
+	}
+
+	if (!found)
+		return;
+
+	ret = drm_dp_check_act_status(&intel_dp->mst_mgr);
+	if (ret)
+		DRM_ERROR("failed to check ACT status\n");
+	ret = drm_dp_update_payload_part2(&intel_dp->mst_mgr);
+	if (ret)
+		DRM_ERROR("failed to update payloads.\n");
+
+	drm_dp_mst_deallocate_vcpi(&intel_dp->mst_mgr, found->port);
+
+	intel_dp->active_mst_links--;
+	if (intel_dp->active_mst_links == 0) {
+		intel_dig_port->base.post_disable(&intel_dig_port->base);
+		intel_dp_sink_dpms(intel_dp, DRM_MODE_DPMS_OFF);
+	}
+}
+
+static void intel_mst_pre_enable_dp(struct intel_encoder *encoder)
+{
+	struct intel_dp_mst_encoder *intel_mst = enc_to_mst(&encoder->base);
+	struct intel_digital_port *intel_dig_port = intel_mst->primary;
+	struct intel_dp *intel_dp = &intel_dig_port->dp;
+	struct drm_device *dev = encoder->base.dev;
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	enum port port = intel_dig_port->port;
+	int ret;
+	uint32_t temp;
+	struct intel_connector *found = NULL, *intel_connector;
+	int slots;
+	struct drm_crtc *crtc = encoder->base.crtc;
+	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
+
+	list_for_each_entry(intel_connector, &dev->mode_config.connector_list, base.head) {
+		if (intel_connector->new_encoder == encoder) {
+			found = intel_connector;
+			break;
+		}
+	}
+
+	if (!found) {
+		DRM_ERROR("can't find connector\n");
+		return;
+	}
+
+	DRM_DEBUG_KMS("%d\n", intel_dp->active_mst_links);
+	if (intel_dp->active_mst_links == 0) {
+		enum port port = intel_ddi_get_encoder_port(encoder);
+
+		I915_WRITE(PORT_CLK_SEL(port), intel_crtc->ddi_pll_sel);
+
+		intel_dp_sink_dpms(intel_dp, DRM_MODE_DPMS_ON);
+
+
+		intel_dp_start_link_train(intel_dp);
+		intel_dp_complete_link_train(intel_dp);
+		intel_dp_stop_link_train(intel_dp);
+	}
+
+	ret = drm_dp_mst_allocate_vcpi(&intel_dp->mst_mgr,
+				       found->port, intel_crtc->config.pbn, &slots);
+	if (ret == false) {
+		DRM_ERROR("failed to allocate vcpi\n");
+		return;
+	}
+
+
+	intel_dp->active_mst_links++;
+	temp = I915_READ(DP_TP_STATUS(port));
+	I915_WRITE(DP_TP_STATUS(port), temp);
+
+	ret = drm_dp_update_payload_part1(&intel_dp->mst_mgr);
+}
+
+static void intel_mst_enable_dp(struct intel_encoder *encoder)
+{
+	struct intel_dp_mst_encoder *intel_mst = enc_to_mst(&encoder->base);
+	struct intel_digital_port *intel_dig_port = intel_mst->primary;
+	struct intel_dp *intel_dp = &intel_dig_port->dp;
+	struct drm_device *dev = intel_dig_port->base.base.dev;
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	enum port port = intel_dig_port->port;
+	int ret;
+
+	DRM_DEBUG_KMS("%d\n", intel_dp->active_mst_links);
+
+	if (wait_for((I915_READ(DP_TP_STATUS(port)) & DP_TP_STATUS_ACT_SENT),
+		     1))
+		DRM_ERROR("Timed out waiting for ACT sent\n");
+
+	ret = drm_dp_check_act_status(&intel_dp->mst_mgr);
+
+	ret = drm_dp_update_payload_part2(&intel_dp->mst_mgr);
+}
+
+static bool intel_dp_mst_enc_get_hw_state(struct intel_encoder *encoder,
+				      enum pipe *pipe)
+{
+	struct intel_dp_mst_encoder *intel_mst = enc_to_mst(&encoder->base);
+	*pipe = intel_mst->pipe;
+	return encoder->connectors_active;
+}
+
+static void intel_dp_mst_enc_get_config(struct intel_encoder *encoder,
+					struct intel_crtc_config *pipe_config)
+{
+	struct intel_dp_mst_encoder *intel_mst = enc_to_mst(&encoder->base);
+	struct intel_digital_port *intel_dig_port = intel_mst->primary;
+	struct intel_crtc *crtc = to_intel_crtc(encoder->base.crtc);
+	struct drm_device *dev = encoder->base.dev;
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	enum transcoder cpu_transcoder = crtc->config.cpu_transcoder;
+	u32 temp, flags = 0;
+
+	pipe_config->has_dp_encoder = true;
+
+	temp = I915_READ(TRANS_DDI_FUNC_CTL(cpu_transcoder));
+	if (temp & TRANS_DDI_PHSYNC)
+		flags |= DRM_MODE_FLAG_PHSYNC;
+	else
+		flags |= DRM_MODE_FLAG_NHSYNC;
+	if (temp & TRANS_DDI_PVSYNC)
+		flags |= DRM_MODE_FLAG_PVSYNC;
+	else
+		flags |= DRM_MODE_FLAG_NVSYNC;
+
+	switch (temp & TRANS_DDI_BPC_MASK) {
+	case TRANS_DDI_BPC_6:
+		pipe_config->pipe_bpp = 18;
+		break;
+	case TRANS_DDI_BPC_8:
+		pipe_config->pipe_bpp = 24;
+		break;
+	case TRANS_DDI_BPC_10:
+		pipe_config->pipe_bpp = 30;
+		break;
+	case TRANS_DDI_BPC_12:
+		pipe_config->pipe_bpp = 36;
+		break;
+	default:
+		break;
+	}
+	pipe_config->adjusted_mode.flags |= flags;
+	intel_dp_get_m_n(crtc, pipe_config);
+
+	intel_ddi_clock_get(&intel_dig_port->base, pipe_config);
+}
+
+static int intel_dp_mst_get_ddc_modes(struct drm_connector *connector)
+{
+	struct intel_connector *intel_connector = to_intel_connector(connector);
+	struct intel_dp *intel_dp = intel_connector->mst_port;
+	struct edid *edid;
+	int ret;
+
+	edid = drm_dp_mst_get_edid(connector, &intel_dp->mst_mgr, intel_connector->port);
+	if (!edid)
+		return 0;
+
+	ret = intel_connector_update_modes(connector, edid);
+	kfree(edid);
+
+	return ret;
+}
+
+static enum drm_connector_status
+intel_mst_port_dp_detect(struct drm_connector *connector)
+{
+	struct intel_connector *intel_connector = to_intel_connector(connector);
+	struct intel_dp *intel_dp = intel_connector->mst_port;
+
+	return drm_dp_mst_detect_port(&intel_dp->mst_mgr, intel_connector->port);
+}
+
+static enum drm_connector_status
+intel_dp_mst_detect(struct drm_connector *connector, bool force)
+{
+	enum drm_connector_status status;
+	status = intel_mst_port_dp_detect(connector);
+	return status;
+}
+
+static int
+intel_dp_mst_set_property(struct drm_connector *connector,
+			  struct drm_property *property,
+			  uint64_t val)
+{
+	return 0;
+}
+
+static void
+intel_dp_mst_connector_destroy(struct drm_connector *connector)
+{
+	struct intel_connector *intel_connector = to_intel_connector(connector);
+
+	if (!IS_ERR_OR_NULL(intel_connector->edid))
+		kfree(intel_connector->edid);
+
+	drm_connector_cleanup(connector);
+	kfree(connector);
+}
+
+static const struct drm_connector_funcs intel_dp_mst_connector_funcs = {
+	.dpms = intel_connector_dpms,
+	.detect = intel_dp_mst_detect,
+	.fill_modes = drm_helper_probe_single_connector_modes,
+	.set_property = intel_dp_mst_set_property,
+	.destroy = intel_dp_mst_connector_destroy,
+};
+
+static int intel_dp_mst_get_modes(struct drm_connector *connector)
+{
+	return intel_dp_mst_get_ddc_modes(connector);
+}
+
+static enum drm_mode_status
+intel_dp_mst_mode_valid(struct drm_connector *connector,
+			struct drm_display_mode *mode)
+{
+	/* TODO - validate mode against available PBN for link */
+	if (mode->clock < 10000)
+		return MODE_CLOCK_LOW;
+
+	if (mode->flags & DRM_MODE_FLAG_DBLCLK)
+		return MODE_H_ILLEGAL;
+
+	return MODE_OK;
+}
+
+struct drm_encoder *intel_mst_best_encoder(struct drm_connector *connector)
+{
+	WARN_ON(1);
+	return NULL;
+}
+
+static const struct drm_connector_helper_funcs intel_dp_mst_connector_helper_funcs = {
+	.get_modes = intel_dp_mst_get_modes,
+	.mode_valid = intel_dp_mst_mode_valid,
+	.best_encoder = intel_mst_best_encoder,
+};
+
+void intel_dp_mst_encoder_destroy(struct drm_encoder *encoder)
+{
+	struct intel_dp_mst_encoder *intel_mst = enc_to_mst(encoder);
+
+	drm_encoder_cleanup(encoder);
+	kfree(intel_mst);
+}
+
+static const struct drm_encoder_funcs intel_dp_mst_enc_funcs = {
+	.destroy = intel_dp_mst_encoder_destroy,
+};
+
+static bool intel_dp_mst_get_hw_state(struct intel_connector *connector)
+{
+	if (connector->encoder)
+		return true;
+	return false;
+}
+
+static struct drm_connector *intel_dp_add_mst_connector(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port, char *pathprop)
+{
+	struct intel_dp *intel_dp = container_of(mgr, struct intel_dp, mst_mgr);
+	struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
+	struct drm_device *dev = intel_dig_port->base.base.dev;
+	struct intel_connector *intel_connector;
+	struct drm_connector *connector;
+	int i;
+
+	intel_connector = kzalloc(sizeof(*intel_connector), GFP_KERNEL);
+	if (!intel_connector)
+		return NULL;
+
+	connector = &intel_connector->base;
+	drm_connector_init(dev, connector, &intel_dp_mst_connector_funcs, DRM_MODE_CONNECTOR_DisplayPort);
+	drm_connector_helper_add(connector, &intel_dp_mst_connector_helper_funcs);
+
+	intel_connector->unregister = intel_connector_unregister;
+	intel_connector->get_hw_state = intel_dp_mst_get_hw_state;
+	intel_connector->mst_port = intel_dp;
+	intel_connector->port = port;
+
+	for (i = PIPE_A; i <= PIPE_C; i++) {
+		drm_mode_connector_attach_encoder(&intel_connector->base,
+						  &intel_dp->mst_encoders[i]->base.base);
+	}
+	intel_dp_add_properties(intel_dp, connector);
+
+	drm_object_attach_property(&connector->base, dev->mode_config.path_property, 0);
+	drm_mode_connector_set_path_property(connector, pathprop);
+	drm_reinit_primary_mode_group(dev);
+	drm_sysfs_connector_add(&intel_connector->base);
+	return connector;
+}
+
+static void intel_dp_destroy_mst_connector(struct drm_dp_mst_topology_mgr *mgr,
+					   struct drm_connector *connector)
+{
+	struct intel_connector *intel_connector = to_intel_connector(connector);
+	struct drm_device *dev = connector->dev;
+	/* need to nuke the connector */
+	mutex_lock(&dev->mode_config.mutex);
+	intel_connector->unregister(intel_connector);
+	drm_connector_cleanup(connector);
+	mutex_unlock(&dev->mode_config.mutex);
+	drm_reinit_primary_mode_group(dev);
+
+	DRM_DEBUG_KMS("\n");
+}
+
+struct drm_dp_mst_topology_cbs mst_cbs = {
+	.add_connector = intel_dp_add_mst_connector,
+	.destroy_connector = intel_dp_destroy_mst_connector,
+};
+
+static struct intel_dp_mst_encoder *
+intel_dp_create_fake_mst_encoder(struct intel_digital_port *intel_dig_port, enum pipe pipe)
+{
+	struct intel_dp_mst_encoder *intel_mst;
+	struct intel_encoder *intel_encoder;
+	struct drm_device *dev = intel_dig_port->base.base.dev;
+
+	intel_mst = kzalloc(sizeof(*intel_mst), GFP_KERNEL);
+
+	if (!intel_mst)
+		return NULL;
+
+	intel_mst->pipe = pipe;
+	intel_encoder = &intel_mst->base;
+	intel_mst->primary = intel_dig_port;
+
+	drm_encoder_init(dev, &intel_encoder->base, &intel_dp_mst_enc_funcs,
+			 DRM_MODE_ENCODER_DPMST);
+
+	intel_encoder->type = INTEL_OUTPUT_DP_MST;
+	intel_encoder->crtc_mask = 0x7;
+	intel_encoder->cloneable = 0;
+
+	intel_encoder->compute_config = intel_dp_mst_compute_config;
+	intel_encoder->mode_set = intel_dp_mst_mode_set;
+	intel_encoder->disable = intel_mst_disable_dp;
+	intel_encoder->post_disable = intel_mst_post_disable_dp;
+	intel_encoder->pre_enable = intel_mst_pre_enable_dp;
+	intel_encoder->enable = intel_mst_enable_dp;
+	intel_encoder->get_hw_state = intel_dp_mst_enc_get_hw_state;
+	intel_encoder->get_config = intel_dp_mst_enc_get_config;
+
+	return intel_mst;
+
+}
+
+static bool
+intel_dp_create_fake_mst_encoders(struct intel_digital_port *intel_dig_port)
+{
+	int i;
+	struct intel_dp *intel_dp = &intel_dig_port->dp;
+
+	for (i = PIPE_A; i <= PIPE_C; i++)
+		intel_dp->mst_encoders[i] = intel_dp_create_fake_mst_encoder(intel_dig_port, i);
+	return true;
+}
+
+int
+intel_dp_mst_encoder_init(struct intel_digital_port *intel_dig_port, int conn_base_id)
+{
+	struct intel_dp *intel_dp = &intel_dig_port->dp;
+	struct drm_device *dev = intel_dig_port->base.base.dev;
+	int ret;
+
+	intel_dp->can_mst = true;
+	intel_dp->mst_mgr.cbs = &mst_cbs;
+
+	/* create encoders */
+	intel_dp_create_fake_mst_encoders(intel_dig_port);
+	ret = drm_dp_mst_topology_mgr_init(&intel_dp->mst_mgr, dev->dev, &intel_dp->aux, 16, 3, conn_base_id);
+	if (ret) {
+		intel_dp->can_mst = false;
+		return ret;
+	}
+	return 0;
+}
+
+void
+intel_dp_mst_encoder_cleanup(struct intel_digital_port *intel_dig_port)
+{
+	struct intel_dp *intel_dp = &intel_dig_port->dp;
+
+	if (!intel_dp->can_mst)
+		return;
+
+	drm_dp_mst_topology_mgr_destroy(&intel_dp->mst_mgr);
+	/* encoders will get killed by normal cleanup */
+}
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 8e41cdc..eda5131 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -32,7 +32,7 @@ 
 #include <drm/drm_crtc.h>
 #include <drm/drm_crtc_helper.h>
 #include <drm/drm_fb_helper.h>
-#include <drm/drm_dp_helper.h>
+#include <drm/drm_dp_mst_helper.h>
 
 /**
  * _wait_for - magic (register) wait macro
@@ -100,6 +100,7 @@ 
 #define INTEL_OUTPUT_EDP 8
 #define INTEL_OUTPUT_DSI 9
 #define INTEL_OUTPUT_UNKNOWN 10
+#define INTEL_OUTPUT_DP_MST 11
 
 #define INTEL_DVO_CHIP_NONE 0
 #define INTEL_DVO_CHIP_LVDS 1
@@ -207,6 +208,10 @@  struct intel_connector {
 	/* since POLL and HPD connectors may use the same HPD line keep the native
 	   state of connector->polled in case hotplug storm detection changes it */
 	u8 polled;
+
+	void *port; /* store this opaque as its illegal to dereference it */
+
+	struct intel_dp *mst_port;
 };
 
 typedef struct dpll {
@@ -340,6 +345,9 @@  struct intel_crtc_config {
 	bool ips_enabled;
 
 	bool double_wide;
+
+	bool dp_encoder_is_mst;
+	int pbn;
 };
 
 struct intel_pipe_wm {
@@ -487,6 +495,7 @@  struct intel_hdmi {
 			       struct drm_display_mode *adjusted_mode);
 };
 
+struct intel_dp_mst_encoder;
 #define DP_MAX_DOWNSTREAM_PORTS		0x10
 
 /**
@@ -527,8 +536,17 @@  struct intel_dp {
 	unsigned long last_backlight_off;
 	bool psr_setup_done;
 	bool use_tps3;
+	bool can_mst; /* this port supports mst */
+	bool is_mst;
+	int active_mst_links;
+	/* connector directly attached - won't be use for modeset in mst world */
 	struct intel_connector *attached_connector;
 
+	/* mst connector list */
+	struct intel_connector *mst_connectors;
+	struct intel_dp_mst_encoder *mst_encoders[I915_MAX_PIPES];
+	struct drm_dp_mst_topology_mgr mst_mgr;
+
 	uint32_t (*get_aux_clock_divider)(struct intel_dp *dp, int index);
 	/*
 	 * This function returns the value we have to program the AUX_CTL
@@ -554,6 +572,12 @@  struct intel_digital_port {
 	struct intel_hdmi hdmi;
 };
 
+struct intel_dp_mst_encoder {
+	struct intel_encoder base;
+	enum pipe pipe;
+	struct intel_digital_port *primary;
+};
+
 static inline int
 vlv_dport_to_channel(struct intel_digital_port *dport)
 {
@@ -621,6 +645,12 @@  enc_to_dig_port(struct drm_encoder *encoder)
 	return container_of(encoder, struct intel_digital_port, base.base);
 }
 
+static inline struct intel_dp_mst_encoder *
+enc_to_mst(struct drm_encoder *encoder)
+{
+	return container_of(encoder, struct intel_dp_mst_encoder, base.base);
+}
+
 static inline struct intel_dp *enc_to_intel_dp(struct drm_encoder *encoder)
 {
 	return &enc_to_dig_port(encoder)->dp;
@@ -684,6 +714,10 @@  void intel_ddi_get_config(struct intel_encoder *encoder,
 			  struct intel_crtc_config *pipe_config);
 
 void intel_ddi_mode_set_dp(struct intel_encoder *encoder);
+void intel_ddi_clock_get(struct intel_encoder *encoder,
+			 struct intel_crtc_config *pipe_config);
+void intel_ddi_force_act(struct intel_encoder *encoder, bool state);
+void intel_ddi_set_vc_payload_alloc(struct drm_crtc *crtc, bool state);
 
 /* intel_display.c */
 const char *intel_output_name(int output);
@@ -800,6 +834,12 @@  void intel_edp_psr_disable(struct intel_dp *intel_dp);
 void intel_edp_psr_update(struct drm_device *dev);
 void intel_dp_set_drrs_state(struct drm_device *dev, int refresh_rate);
 
+int intel_dp_handle_hpd_irq(struct intel_digital_port *digport, bool long_hpd);
+void intel_dp_add_properties(struct intel_dp *intel_dp, struct drm_connector *connector);
+
+/* intel_dp_mst.c */
+int intel_dp_mst_encoder_init(struct intel_digital_port *intel_dig_port, int conn_id);
+void intel_dp_mst_encoder_cleanup(struct intel_digital_port *intel_dig_port);
 /* intel_dsi.c */
 bool intel_dsi_init(struct drm_device *dev);
 
diff --git a/drivers/gpu/drm/i915/intel_opregion.c b/drivers/gpu/drm/i915/intel_opregion.c
index acde294..bce66b2 100644
--- a/drivers/gpu/drm/i915/intel_opregion.c
+++ b/drivers/gpu/drm/i915/intel_opregion.c
@@ -352,6 +352,7 @@  int intel_opregion_notify_encoder(struct intel_encoder *intel_encoder,
 	case INTEL_OUTPUT_UNKNOWN:
 	case INTEL_OUTPUT_DISPLAYPORT:
 	case INTEL_OUTPUT_HDMI:
+	case INTEL_OUTPUT_DP_MST:
 		type = DISPLAY_TYPE_EXTERNAL_FLAT_PANEL;
 		break;
 	case INTEL_OUTPUT_EDP: